Atkins Diet

Diet Reference Archive: diet

Atkins Diet

A low-carbohydrate eating plan that began with Robert Atkins's 1972 book and is now sold by a food company in 3 versions, starting at about 20, 40 or 100 grams of net carbohydrate a day. It is promoted mainly for weight loss and for blood sugar control.

Family: Low-carbohydrate and high-protein diets Promoted by: Atkins Nutritionals, Inc., part of The Simply Good Foods Company First appeared: 1972 GRADE: Low for a difference in measured body weight at 12 months, adults with overweight or obesity and without diabetes, Atkins diets taught from the books in trials published from 2003 to 2010 against low-fat, reduced-calorie diets; this page's own judgment

ON THIS PAGE

1. In brief
2. Overview
3. In practice
4. For the coach
5. The evidence (opens on request)
6. Mechanisms (opens on request)
7. Risks, contraindications and myths (opens on request)
8. Key terms
9. Review questions
10. References
11. Evidence rating and review record

The summary and sections 1 to 3 are the short version and are open when the page loads. Sections 4 to 6 hold the research detail, the biology, and the cautions. Each of those opens when you select its heading, and you can read the page without opening them. Back to the Diet Reference Archive index.

In brief

What is it? A way of eating that cuts carbohydrate sharply at first and lets protein, fat and nonstarchy vegetables fill the plate, then adds carbohydrate back in steps. The cardiologist Robert Atkins published the first book in 1972. The company that carries his name now offers 3 free plans, at about 20, 40 or 100 grams of net carbohydrate a day, and sells bars, shakes and treats (Atkins Nutritionals, Inc., n.d.-a, n.d.-d, n.d.-h, n.d.-i). The strictest plan begins with a ketogenic phase.

Does it work? Trials that named the Atkins diet or taught it from the books, published between 2003 and 2010, found that adults lost more measured weight on Atkins than on a low-fat diet over the first 3 to 6 months. By 12 months, in the trials against low-fat diets in adults without diabetes, the gap had narrowed to somewhere between about 0 and 2 kilograms, roughly 0 to 4.5 pounds (Foster et al., 2003, 2010; Gardner et al., 2007). Two trials followed Atkins-based versions for 2 years, with different populations and support: one found no clear difference from a low-fat diet, and the other, a workplace trial that included some people with diabetes, recorded 4.7 kilograms lost on its Atkins-based diet against 2.9 on a low-fat diet (Foster et al., 2010; Shai et al., 2008).

A 2020 review that pooled Atkins with similar diets rated moderate certainty for modest changes in weight and blood pressure at 6 months against usual eating, with smaller effects at 12 months (Ge et al., 2020). This page rates the 12-month weight evidence low in certainty. The searches for this page did not identify a study estimating the diet's effect on heart attacks, strokes, cancer or survival.

Is it safe? The trials recorded mostly minor problems in the first months, such as constipation, bad breath and dry mouth, and more reports of hair loss at 6 months (Foster et al., 2010). LDL cholesterol, the kind linked to heart disease, was higher on Atkins than on a low-fat diet over the first 3 to 6 months, and in some people it rose steeply (Foster et al., 2010; McAuley et al., 2005). Serious harms such as ketoacidosis, a dangerous acid buildup in the blood, appear in case reports, not as measured rates (Ullah et al., 2018).

For anyone taking diabetes medicine, a sudden drop in carbohydrate can cause low blood sugar on insulin or a sulfonylurea, and ketoacidosis on the drugs called SGLT2 inhibitors (American Diabetes Association Professional Practice Committee for Diabetes, 2026). A possible low blood sugar episode is treated first under the person's own plan, with emergency help if symptoms are severe or the person cannot manage the episode under that plan; the prescriber is told afterward.

Who should not do it without talking to a doctor or dietitian first? Anyone taking insulin, a sulfonylurea, an SGLT2 inhibitor, blood pressure medicine or warfarin, who keeps the prescriber informed before a substantial change in eating. Anyone who is pregnant or breastfeeding. Children and teenagers. Anyone with kidney disease, whose needs depend on its stage, laboratory results and whether they are on dialysis; the company itself says its weight loss phases should not be used by people on dialysis (Atkins Nutritionals, Inc., n.d.-a). Anyone with high LDL cholesterol or heart disease. And anyone with a current or past eating disorder.

Related pages: Ketogenic Diet, Paleo Diet, Carnivore Diet, WeightWatchers, Meal Replacement Programs, Mediterranean Diet, and, named here without links, Low-Carbohydrate Diets, South Beach Diet, Zone Diet and Dukan Diet. Full list on the archive index.

1. Overview

What you eat

The company that owns the name offers 3 plans. "Just the right amount of Atkins" is set at about 100 grams of net carbohydrate a day and is pitched for weight maintenance or steady loss. Atkins Flex is set at about 40 grams. Atkins KickStart, which the company calls "The Original Atkins," starts at about 20 grams (Atkins Nutritionals, Inc., n.d.-a). Net carbohydrate is the company's own measure: total carbohydrate minus fiber, and in packaged foods minus sugar alcohols as well (Atkins Nutritionals, Inc., n.d.-k). Older names for the same 3 levels, Atkins 20, Atkins 40 and Atkins 100, still appear in the company's articles and web addresses.

In the first phase of KickStart, called Induction, meals are built around protein, about 3 servings a day of 4 to 6 ounces each of poultry, fish, shellfish, eggs or red meat. At least 12 to 15 grams of the day's net carbohydrate must come from salad greens and other nonstarchy vegetables, which the company calls Foundation Vegetables. Added fat such as butter, mayonnaise and olive or other vegetable oils is allowed at about 3 tablespoons a day, along with cheese and cream (Atkins Nutritionals, Inc., n.d.-k, n.d.-l). Water is emphasized, at least 8 glasses of 8 ounces a day, with broth allowed for part of it (Atkins Nutritionals, Inc., n.d.-l).

After at least 2 weeks, or once a person is within 15 pounds of the weight they have chosen, KickStart adds carbohydrate in steps of 5 to 10 grams of net carbohydrate a day, bringing back foods such as nuts, seeds and lower-sugar fruit like berries, until the person reaches what the company calls a "Personal Carb Balance," which it says may settle anywhere from 30 to 100 grams a day (Atkins Nutritionals, Inc., n.d.-b, n.d.-k). The trials described in section 4 taught older versions from the books. In the 2-year trial in the United States, participants started at 20 grams a day of carbohydrate from vegetables for 12 weeks, then added about 5 grams a week, moving from more vegetables to a little fruit and eventually small amounts of whole grains and dairy (Foster et al., 2010).

What you avoid or limit

In Induction, the company's list rules out fruit, bread, pasta, grains, starchy vegetables, and dairy foods other than cheese, cream and butter. Nuts and seeds are left out for the first 2 weeks, and so are foods that combine protein and carbohydrate, such as chickpeas, kidney beans and other legumes. Sugar substitutes are limited to 3 packets a day, each counted as 1 gram of carbohydrate, and the plan warns about hidden sugar and starch in sauces, gravies and dressings (Atkins Nutritionals, Inc., n.d.-l). The company presents these as rules, not suggestions: "The Induction phase must be followed precisely to achieve success" (Atkins Nutritionals, Inc., n.d.-l).

The limits loosen by design. The later KickStart phases and the 40 and 100 gram plans allow more fruit, starchy vegetables, legumes and whole grains, and the company describes the 100 gram plan as one where "nothing is off the table" (Atkins Nutritionals, Inc., n.d.-a). What stays constant across the plans is a cap on daily net carbohydrate and an emphasis on protein, nonstarchy vegetables and limited added sugar.

Where it came from

Robert C. Atkins was a cardiologist. His first book, Dr. Atkins' Diet Revolution, appeared in 1972, and the company describes it as advice to limit "sugar and carbs instead of restricting fats and protein" (Atkins Nutritionals, Inc., n.d.-h, n.d.-i; Finney Rutten et al., 2008). In 1973, the American Medical Association's Council on Foods and Nutrition published a critique of low-carbohydrate ketogenic weight-reduction regimens, subtitled a review of the book ("A critique of low-carbohydrate ketogenic weight reduction regimens," 1973).

The revised book, Dr. Atkins' New Diet Revolution, is the version most trials used; the papers cite a 1998 printing and a 2002 edition (Davis et al., 2009; Foster et al., 2010). A 2004 commentary in The Lancet stated that the Atkins books had "sold more than 45 million copies over 40 years," and that the diet allowed fatty meat, butter and high-fat dairy foods while holding carbohydrate under 30 grams a day (Astrup et al., 2004). The same years brought the first randomized trials, discussed in section 4, and sharp debate; one 2004 editorial was titled "Is Atkins dead (again)?" (Lean & Lara, 2004).

The brand is now owned by The Simply Good Foods Company, a publicly traded food company in Denver. Atkins Nutritionals, Inc. became part of it through a merger agreement dated July 7, 2017, and the Atkins trademark is held by one of its subsidiaries (The Simply Good Foods Company, 2025). A medical version grew out of the diet separately: the modified Atkins diet, used for drug-resistant epilepsy, starts at about 10 to 15 grams of carbohydrate a day, which its developers describe as comparable to the strict first phase of the weight-loss diet (Kossoff et al., 2018). That medical use is covered on the Ketogenic Diet page, not here.

What it claims to do

The company's claims, in its own words, center on metabolism. KickStart is described as "the quickest way to the legendary Atkins Metabolism Changing Nutrition™ that makes your body burn fat, instead of storing it" (Atkins Nutritionals, Inc., n.d.-a). It is said to lower insulin and shift the body "into a fat-burning metabolic state called ketosis," helping to "reduce cravings, stabilize energy and promote weight loss," without counting calories (Atkins Nutritionals, Inc., n.d.-b). The company calls Atkins 20 "the original, clinically studied low carb approach" (Atkins Nutritionals, Inc., n.d.-k).

For health beyond weight, the company answers "Yes" to whether KickStart is safe for people with prediabetes or type 2 diabetes, adding that anyone taking glucose-lowering medicine should work with a health care provider, and it lists effects on blood sugar, insulin sensitivity, triglycerides and HDL cholesterol (Atkins Nutritionals, Inc., n.d.-b). Its history page goes further, saying that decades of research "ultimately showed Dr. Atkins was right" (Atkins Nutritionals, Inc., n.d.-i). Whether the trials support these claims is the subject of section 4.

What it gets right

Every Atkins plan removes or sharply limits added sugar, sugary drinks, sweets and refined starches, foods that general heart-health guidance also asks people to limit. The plan does not ask people to live on meat alone: it requires 12 to 15 grams of net carbohydrate a day from nonstarchy vegetables from the first day (Atkins Nutritionals, Inc., n.d.-l). Protein at each meal can make a smaller meal more satisfying, and the phased design builds in a planned return to a wider range of foods rather than an indefinite 20 gram limit.

The trials also show something useful for a coach. Across 4 popular diets in one trial, and within each diet in another, weight change tracked how closely people said they followed their plan more than which plan they were on (Alhassan et al., 2008; Dansinger et al., 2005). And on some blood measures Atkins did better than the comparison diets: triglycerides fell more and HDL cholesterol rose more (Foster et al., 2010; Mehta et al., 2016). A coach can honor a client's interest in cutting sugar and refined starch without endorsing the whole package.

How clients describe it, and what it gets confused with

A client may say "I'm doing Atkins," "I'm in Induction," "I'm counting net carbs," "I'm in ketosis" or simply "I'm cutting carbs." Some mean the full phased plan; some mean eating the company's bars and shakes while otherwise eating as before; some mean a general low-carbohydrate approach. A client who says "low carb" could mean any diet in this family, or the broader topic Low-Carbohydrate Diets.

Atkins is most often confused with the Ketogenic Diet. The first phase of KickStart is ketogenic, and the company says both its 20 and 40 gram plans are considered ketogenic, adding that this often depends on individual factors, but the plans are built to rise above ketogenic levels over time (Atkins Nutritionals, Inc., n.d.-k). It is also confused with the Carnivore Diet, which removes plant foods altogether, while Atkins requires vegetables daily; with the Paleo Diet, which removes grains and legumes for a different reason; and with South Beach, Zone and Dukan, other branded low-carbohydrate or high-protein plans named here without links. The modified Atkins diet for epilepsy is a medical treatment on the Ketogenic Diet page.

The company's shakes are snacks and protein drinks, although its store also sells a line it calls Meal Shakes; replacing meals with shakes as a method is covered on the Meal Replacement Programs page (Atkins Nutritionals, Inc., n.d.-d).

2. In practice

A typical day of eating

The day below follows the company's rules for the first phase of KickStart; it is an illustration written for this page, not one of the company's meal plans. Breakfast is 2 eggs scrambled in butter with spinach and mushrooms, with coffee and a splash of cream. Lunch is a large salad of mixed greens, cucumber and peppers topped with grilled chicken and an olive oil dressing. An afternoon snack is a piece of cheese with celery. Dinner is baked salmon or a small steak with roasted broccoli and zucchini. Water, unsweetened tea and broth make up the drinks. The vegetables in that day supply most of its carbohydrate, which is the point of the 12 to 15 gram vegetable rule (Atkins Nutritionals, Inc., n.d.-l).

A day on the 40 or 100 gram plan looks more ordinary: the same meals might add berries with Greek yogurt at breakfast, a half cup of beans at lunch, a slice of whole-grain bread or a small potato at dinner. Many people also use the company's bars or shakes as snacks. They are not required by any of the plans.

Cost, products, and who profits

The plans themselves cost nothing. The company publishes its plan descriptions, food lists and recipes on its website, and the pages opened for this page on October 19, 2026 did not show a paid membership (Atkins Nutritionals, Inc., n.d.-a). The food bill shifts rather than disappears: the first phase leans on meat, fish, eggs, cheese and fresh nonstarchy vegetables, and it removes rice, beans, oats, potatoes and bread, staples that many households on a tight budget rely on. A household with limited money can build the plan on eggs, canned fish, frozen vegetables and cabbage, but it gives up those staples during the strictest phase.

The products are where the brand earns its money. On October 19, 2026, the company's online store, which says it is powered by WorldPantry, Inc., listed its classic shakes at $9.99 for a box of 4, about $2.50 a shake; its 30-gram-protein Strong shakes at $11.29 for 4; most high-protein bars at $9.29 for 4, about $2.32 a bar; and its Endulge treats from $8.79 a box. It offered free 1 to 3 day delivery on orders over $99 and 15 percent off for subscriptions (Atkins Nutritionals, Inc., n.d.-d, n.d.-e). At those prices, one bar and one shake a day would come to about $4.80 a day, roughly $145 a month, by this page's arithmetic. The products are also sold through retailers, whose prices differ.

Atkins is one of 3 brands owned by The Simply Good Foods Company, which trades on the Nasdaq exchange. In the fiscal year ended August 30, 2025, Atkins products brought in $420.8 million in North American net sales, down from $492.0 million the year before and $526.8 million the year before that, while the company's Quest brand grew. The company's 2 largest customers, Walmart and Amazon, accounted for about 31 and 18 percent of all its sales, and the company reported that Walmart reduced the number of Atkins products it carries (The Simply Good Foods Company, 2025).

In the quarter ended May 30, 2026, Atkins net sales fell 24.6 percent from a year earlier, with North American Atkins sales of $84.6 million, which the company attributed largely to known losses of store distribution, and it recorded impairment charges on goodwill and on the Atkins and OWYN brand assets (The Simply Good Foods Company, 2026).

The company's own filing makes 2 points that shape the marketing a client may have seen. It says it aims to sell Atkins products to "health motivated eaters (including those individuals not on a program diet)," and to people who "have elected to use medication" to manage their weight (The Simply Good Foods Company, 2025). The Atkins website has a page that describes its products as "GLP-1 friendly," meaning suited to people taking the newer weight-loss medicines (Atkins Nutritionals, Inc., n.d.-g). In other words, the brand's products are marketed to many people who may never follow the phased diet.

Money also touches the research. The Robert C. Atkins Foundation was among the funders of the 1-year trial in type 2 diabetes described in section 4 (Davis et al., 2009). The Dr. Robert C. and Veronica Atkins Research Foundation was among the funders of a 2-year workplace trial in Israel (Shai et al., 2008), and the Robert C. Atkins Foundation funded a 24-week trial at Duke University in which Atkins Nutritionals supplied the supplements given to the Atkins group (Yancy et al., 2004). The 2-year trial in the United States was funded by the National Institutes of Health (Foster et al., 2010); in a 2013 report on cognitive performance from the same research group and grant, one author disclosed endowments from the Atkins Foundation Charitable Trust (Makris et al., 2013).

Robert Atkins was a coauthor of a 2007 trial report on mood and hunger (McClernon et al., 2007), and the lead author of the international consensus on medical ketogenic diets disclosed a seat on a scientific advisory board of Atkins Nutritionals (Kossoff et al., 2018). The plant-based Eco-Atkins trial was funded by Solae, LLC, Loblaw Companies Limited and a Canadian government research chair program (Jenkins et al., 2014). None of these ties makes a finding wrong. It is worth knowing who has a stake in it.

Environmental footprint

The footprint likely depends mostly on which foods a person chooses within the plan: by inference from the foods involved, not from a measurement, a version built mainly on red meat and dairy would carry more than one built on fish, eggs, soy and vegetables. The searches for this page did not identify a footprint study of Atkins followers. The Ketogenic Diet page describes research on ketogenic-level eating; that research does not estimate the footprint of the Atkins plan.

Cultural fit

The plan fits easily with cooking built around grilled or roasted meat and fish, eggs, cheese and salads, and with cuisines that already serve vegetables alongside a protein. It conflicts most with food traditions in which rice, maize tortillas, bread, noodles, beans, lentils, potatoes, plantain or cassava are the base of the meal, and with family meals in which one shared starch is served to everyone. The later phases and the 100 gram plan allow some of those foods back in measured amounts, which makes adaptation possible without abandoning the plan.

For vegetarians, the company says they should start at Phase 2 rather than Phase 1 (Atkins Nutritionals, Inc., n.d.-l), and it lists vegetarians and vegans among the people its 40 and 100 gram plans suit (Atkins Nutritionals, Inc., n.d.-a). A research version called Eco-Atkins replaced animal protein and fat with gluten, soy, nuts and vegetable oils (Jenkins et al., 2009, 2014); it is described in section 4 as a variation, not as the company's plan.

What makes people stop

The trials show the same pattern as most weight-loss diets: many people drift away. In the first 1-year trial, the authors wrote: "Adherence was poor and attrition was high in both groups" (Foster et al., 2003). In a Boston trial of 4 popular diets, 21 of 40 people assigned to Atkins, 53 percent, completed the year, against 65 percent for the Weight Watchers and Zone groups and 50 percent for Ornish (Dansinger et al., 2005).

In the 2-year trial in the United States, 42 percent of the Atkins group and 32 percent of the low-fat group missed the final assessment, a difference that was not statistically significant (Foster et al., 2010). In a 2-year workplace trial in Israel, 78 percent of the Atkins-based group completed it, against 90 percent of the low-fat group (Shai et al., 2008); in a 24-week trial, 76 percent completed the Atkins-based program, against 57 percent on the low-fat diet (Yancy et al., 2004).

The reasons recorded in the trials are partly physical. Constipation, bad breath and dry mouth were more common on Atkins in the early months (Foster et al., 2010), and the company itself describes a "low carb transition" in the first days that may bring fatigue, headaches and irritability (Atkins Nutritionals, Inc., n.d.-b). Carbohydrate also creeps back by design and by habit: in the 2-year trial, 63 percent of the Atkins group had ketones in their urine at 3 months, 28 percent at 6 months, and no more than the low-fat group after that, which the authors linked to the planned increase in carbohydrate (Foster et al., 2010). Beyond the trials, the reasons people give for stopping, such as shared meals, travel and cost, are observation rather than measured data.

What happens when you stop

Two trials followed Atkins-based versions for 2 years, with different populations and support (Foster et al., 2010; Shai et al., 2008). In the trial in the United States, which followed 307 adults, both the Atkins and the low-fat group lost about 11 percent of their starting weight by 6 to 12 months and had regained part of it by 2 years, ending about 7 percent below where they began, with no clear difference between the diets (Foster et al., 2010). The early LDL difference had disappeared by 12 months, the larger fall in triglycerides was no longer statistically clear from 12 months on, and the larger rise in HDL cholesterol was still present at 2 years (Foster et al., 2010).

In the workplace trial in Israel, weight loss in all 3 diet groups was greatest in the first 6 months and was followed by partial regain and a plateau (Shai et al., 2008).

A 2014 systematic review of 4 popular diets concluded that weight lost with Atkins or Weight Watchers "is partially regained over time" in trials with 24-month data (Atallah et al., 2014, read as an abstract). The workplace trial's investigators followed 259 of its participants for 4 more years after the 2-year program ended. Over those years the Atkins-based group regained 4.1 kilograms, against 2.7 for the low-fat group and 1.4 for the Mediterranean group; across all 6 years, total weight loss was 1.7, 0.6 and 3.1 kilograms, and the difference between the Atkins-based and low-fat groups was not statistically significant (Schwarzfuchs et al., 2012). Apart from that follow-up, the searches for this page did not identify a trial of a named Atkins plan that followed people for longer than 2 years.

The company's own answer is that returning to "a high-carb, highly processed diet" commonly brings weight regain and the return of cravings, and that its later phases and plans are meant to prevent that (Atkins Nutritionals, Inc., n.d.-b); that is the company's claim, not a trial finding.

Common variations

The 3 current plans. KickStart at about 20 grams of net carbohydrate a day, which begins with a ketogenic Induction phase and then adds carbohydrate back; Atkins Flex at about 40 grams; and "Just the right amount of Atkins" at about 100 grams (Atkins Nutritionals, Inc., n.d.-a). The company says a person can start at any phase (Atkins Nutritionals, Inc., n.d.-j).

The book versions. The trials in section 4 tested plans taught from Dr. Atkins' New Diet Revolution and similar materials in the early 2000s, with Induction at about 20 grams and gradual increases through 4 phases (Makris et al., 2013); the company's questions page still refers to Phase 3 and to Lifetime Maintenance, and its Induction page to "the four Phases" (Atkins Nutritionals, Inc., n.d.-f, n.d.-j). None of the trials found tested the 3 plans as the company presents them in 2026, or the company's products as part of the plan.

Eco-Atkins. A vegan low-carbohydrate diet designed by researchers in Toronto, with about 26 percent of energy from carbohydrate and protein from gluten, soy and nuts (Jenkins et al., 2009, 2014). It shares the name and the carbohydrate cut, not the foods.

The modified Atkins diet. A medical diet for drug-resistant epilepsy, started at about 10 to 15 grams of carbohydrate a day and managed by a neurology team (Kossoff et al., 2018). It belongs on the Ketogenic Diet page. Research versions have also been tried in other conditions, such as a 12-week feasibility trial in older adults with memory problems due to early Alzheimer's disease (Buchholz et al., 2024); these are clinical research, not weight-loss plans.

Products on their own. Many people buy Atkins bars and shakes without following any phase, and the company now markets them to people taking weight-loss medicines (Atkins Nutritionals, Inc., n.d.-g). That is a product choice, not the diet, and the trials say nothing about it.

3. For the coach

SCOPE OF PRACTICE

A health and wellness coach does not prescribe, adjust, endorse, or discourage the Atkins diet or any other way of eating, and does not diagnose or treat. The coach helps the client understand what they have chosen, notice how it is going, and decide what to do next. The company's suggestion that its strictest plan suits people with prediabetes or type 2 diabetes does not move any medical decision to the client or the coach: a change in diabetes, blood pressure or blood-thinning medicine belongs to the prescriber, and a plan for a diagnosed condition belongs to the clinician and registered dietitian who manage it. For kidney disease, needs depend on the stage of the disease, laboratory results and whether the person is on dialysis.

The documented risks of this diet fall mainly on particular groups rather than on adults in general. For a client in any of these 6 groups, the coach's role includes making sure the client has medical oversight for the change:

• Taking insulin, a sulfonylurea, an SGLT2 inhibitor, blood pressure medicine or warfarin: the client keeps the prescriber informed before a substantial change in eating.
• Pregnant or breastfeeding: the obstetric or pediatric clinician and a registered dietitian.
• Under 18: the family and the pediatric clinician.
• Kidney disease, including dialysis: the kidney care team.
• High LDL cholesterol, inherited high cholesterol or heart disease: the physician who manages it, who can check the lipid response.
• A current or past eating disorder or disordered eating: the client's clinician, through the coach's own referral process or an existing care plan.

Who does what

The physician

Decides whether the plan is medically safe for this person, given their conditions and medicines. Adjusts insulin and sulfonylureas before or during a large drop in carbohydrate; in one trial in type 2 diabetes the protocol halved insulin doses and stopped sulfonylureas in the Atkins group on the first day (Davis et al., 2009). Decides about SGLT2 inhibitors, which the American Diabetes Association says should not be combined with very low carbohydrate eating, monitors blood pressure, and checks the INR of a client on warfarin (American Diabetes Association Professional Practice Committee for Diabetes, 2026; Beatty et al., 2005). Orders and reads the labs that matter for this diet: a lipid panel, since LDL cholesterol can rise, kidney function, and HbA1c for diabetes.

The registered dietitian

Designs an individual plan at the carbohydrate level the client chooses that still meets needs for fiber and for the vitamins and minerals that fell in one trial of the early phase, such as thiamin, folate, vitamin C, iron and magnesium (Gardner et al., 2010). Adapts it to diabetes, kidney disease, pregnancy, a vegetarian diet or a history of disordered eating, and helps a client decide which of the company's products, if any, fit.

The health and wellness coach

Helps the client say what they want from Atkins and why now, and whether "doing Atkins" means the phased plan, a general cut in sugar and bread, or a set of products. Explores how the plan fits the client's budget, family meals, culture and work, and helps the client build the habits that make their chosen approach workable, such as planning vegetables for each meal or preparing for social events. With the client's permission, can share general guidance from recognized authorities, such as the American Diabetes Association's statement on very low carbohydrate eating, and explore how the client wants to use it. Notices whether eating is widening or narrowing, and holds the referral line.

What a client bringing this diet needs

Clients bring Atkins for a handful of reasons: a friend or relative lost weight on it years ago; a diagnosis of prediabetes or type 2 diabetes and the company's message that its strictest plan suits them; a wish to stop craving sugar; or a habit of eating the brand's bars and shakes. Some return to it because it worked for them before. The reason shapes the conversation. A client on insulin who plans to begin Induction on Monday needs something very different from a client who wants to swap a candy bar for a protein bar.

What the coaching conversation offers that a search engine cannot is room to separate the client's goal from the plan they found. The client can look honestly at what the research shows, including the fact that most of the early weight difference fades by a year, and decide what they want to try, for how long, and how they will know whether it suits them. For a client on medicines, it is also the place to make sure the people treating them know what they intend before they begin.

What to ask

• "What draws you to Atkins right now, and what are you hoping will be different in a few months?"
• "When you say Atkins, which version do you have in mind: the 20 gram start, the 40 or 100 gram plans, or mainly the bars and shakes?"
• "How would this way of eating work with the meals you share at home, at work and with friends?"
• "Are you taking any medicines, and does the person who prescribes them know you are planning to change how you eat?"
• "How have past changes in eating gone for you, and what would tell you this one is or is not working for you?"

Referral red flags

A client who takes insulin, a sulfonylurea, an SGLT2 inhibitor, blood pressure medicine or warfarin and is starting or has started the plan goes to the prescriber before going further (American Diabetes Association Professional Practice Committee for Diabetes, 2026; Beatty et al., 2005). A client on insulin or a sulfonylurea who describes what may be a low blood sugar episode treats the episode first, under their own plan, with emergency help if symptoms are severe or the person cannot manage the episode under that plan; telling the prescriber is the separate step that follows. A client on an SGLT2 inhibitor, or anyone on a strict plan who describes vomiting, heavy thirst, rapid breathing, fainting or confusion, needs urgent medical care, because ketoacidosis has been reported in these settings (American Diabetes Association Professional Practice Committee for Diabetes, 2026; Ullah et al., 2018; see the Ketogenic Diet page).

Pregnancy and breastfeeding go to the obstetric clinician or a dietitian. Kidney disease, a history of kidney stones, high LDL cholesterol, inherited high cholesterol or heart disease go to the physician before the plan starts, and a client who mentions a large rise in cholesterol on a recent blood test is describing something for the physician to interpret. Weight the client is losing without meaning to is a reason to involve a clinician. And a client whose talk of carbohydrate counts comes with distress, a narrowing list of foods, or eating that gets in the way of daily life is a concern for the coach's own referral process, or for the client's clinician under an existing care plan.

Special populations

Pregnancy and breastfeeding

The American Diabetes Association does not currently recommend very low carbohydrate eating plans during pregnancy or lactation (American Diabetes Association Professional Practice Committee for Diabetes, 2026). The company lists people who are pregnant or nursing among those its 100 gram plan suits, and asks them to consult a physician before starting any plan (Atkins Nutritionals, Inc., n.d.-a). The Europe PMC search for this page that combined Atkins with pregnancy and breastfeeding found no trial of the weight-loss diet in pregnancy; the reports it found concerned the medical modified Atkins diet for epilepsy. Ketoacidosis has been reported in breastfeeding mothers on strict low-carbohydrate diets, as the Ketogenic Diet page describes. Any plan to follow Atkins while pregnant or breastfeeding belongs to the obstetric clinician and a registered dietitian.

Children and adolescents

The American Diabetes Association does not currently recommend very low carbohydrate eating plans for children (American Diabetes Association Professional Practice Committee for Diabetes, 2026). The searches for this page found no trial of the company's plans in children or adolescents. Small, short, medically supervised trials in adolescents with obesity have tested diets at ketogenic carbohydrate levels; they are described on the Ketogenic Diet page, and one of them cited the Atkins book as background without stating that it used it (Sondike et al., 2003). The modified Atkins diet is used in children with epilepsy under a neurology team (Kossoff et al., 2018). A young person's eating belongs to the family and the pediatric clinician.

Older adults

The searches for this page did not identify a trial of the Atkins weight-loss plan in older adults. In a 12-week feasibility trial of the medical modified Atkins diet in 38 older adults with mild memory problems due to early Alzheimer's disease, only 22 were assessed at the end and only 2 met the ketone levels used to define adherence (Buchholz et al., 2024). In the 2-year trial of younger and middle-aged adults, lean mass fell by about 5 percent in both the Atkins and the low-fat group as weight was lost, and bone density did not differ between groups (Foster et al., 2010). For an older adult, the physician weighs muscle, bone, kidney function and medicines before a large change.

Athletes and people with high activity

Evidence is thin. In one small 2003 study, 17 physically active people followed a carbohydrate-restricted diet and a usual diet for 3 weeks each; after exercise on the restricted diet they reported more fatigue and negative feelings and fewer positive ones (Butki et al., 2003). The company itself says performance "may feel slightly reduced" at first (Atkins Nutritionals, Inc., n.d.-b). A sports dietitian is the right person for a training plan.

People taking medication for diabetes, blood pressure, or blood thinning

This is the group where the plan most clearly needs the prescriber first. The American Diabetes Association states that insulin and other diabetes medicines may need adjusting to prevent low blood sugar on very low carbohydrate plans, that blood pressure "will need to be monitored," and that these plans "should be avoided in those taking" SGLT2 inhibitors (American Diabetes Association Professional Practice Committee for Diabetes, 2026). In 2 published cases, patients needed higher warfarin doses after starting high-protein, low-carbohydrate diets (Beatty et al., 2005). The standing rule holds: for a substantial change in eating by a client on these medicines, the client keeps the prescriber informed before the change. Section 6 lists the interactions.

People with a history of disordered eating

The first phase is built on strict rules about allowed foods, and the company says it "must be followed precisely" (Atkins Nutritionals, Inc., n.d.-l). The American Diabetes Association does not currently recommend very low carbohydrate eating plans for people with or at risk for disordered eating (American Diabetes Association Professional Practice Committee for Diabetes, 2026). The searches for this page did not identify a study measuring disordered eating in people following Atkins. A concern goes to the client's clinician under the existing care plan, or through the coach's own referral process.

Client misconceptions

Clients often bring 3 of them. The first is that calories do not count on Atkins. In the trials people ate less without being told to: reported energy intake fell on Atkins as it did on the comparison diets (Shai et al., 2008; Truby et al., 2008), and in one 2-year trial with the same support for both diets, weight change was about the same (Foster et al., 2010). The second is that Atkins and keto are the same thing; only the first phase is ketogenic by design, and ketones faded in most trial participants after 6 months (Foster et al., 2010).

The third is the company's statement that research has shown Dr. Atkins was right. The trials show a modest early weight advantage that in most of them faded by a year, better triglycerides and HDL, and higher LDL in the early months, and the searches for this page did not identify a study estimating the diet's effect on heart attacks, strokes or survival. Section 6 sets out each myth and where it came from.

🤝 COACHING CONNECTION

Dana tells her coach she is restarting Atkins next Monday. It worked for her 15 years ago, and the company's website says the 20 gram plan is a good fit for type 2 diabetes. She takes metformin and glipizide. The coach asks what she remembers about how Atkins went for her the first time, and what made her stop. Dana says the first weeks felt easy, then holidays came. The coach asks what her doctor knows about her plan. Dana says she had not thought to mention it. The coach asks whether she would like to tell him before Monday, and what she would want to ask. Dana decides to send a message through the clinic's patient portal and to ask what to watch for. They spend the rest of the session on what she wants to be different this time, and on how she will handle family dinners.

4. The evidence

(select the heading to open or close this section)

The research on the Atkins diet itself is a set of randomized trials published from 2003 to 2010, with a few smaller studies since, that named Atkins or taught it from its books. They show more measured weight loss than low-fat diets in the first 3 to 6 months, a gap that mostly closed by 12 months in the trials of adults without diabetes, with mixed results at 2 years; lower triglycerides and higher HDL cholesterol; higher LDL cholesterol in the early months; and more minor symptoms such as constipation early on. The searches for this page did not identify a study estimating the diet's effect on heart attacks, strokes, cancer or survival, and none of the trials tested the company's 3 current plans.

What this page counts as Atkins evidence. This page reports trials that named the Atkins diet or used Atkins's books or materials, and says which version each tested. The much larger body of research on low-carbohydrate diets in general belongs to the broader topic Low-Carbohydrate Diets, and the ketogenic research, including the medical modified Atkins diet, belongs to the Ketogenic Diet page. Where a pooled review reports Atkins trials separately, that separate result is used here, with a note on which trials the review counted. Several sources could be opened only as abstracts; the page says so where each is used.

Evidence from randomized controlled trials

A trial assigns people to the diet by chance and compares them with people assigned to something else, which is the strongest way to test whether the diet itself causes a result. The searches for this page found 9 weight-loss trials of 3 months or longer that named Atkins or used its books. Where the reports describe it, the Atkins version was the early-2000s book plan, starting at about 20 grams of carbohydrate a day and rising in steps.

• Foster et al. (2003). 63 adults with obesity, 1 year, the "low-carbohydrate, high-protein, high-fat (Atkins) diet" against a low-calorie, low-fat diet, with minimal professional contact "to replicate the approach used by most dieters." Each person on Atkins was given a copy of Dr. Atkins' New Diet Revolution; people with type 2 diabetes were excluded; 37 of the 63 completed the year, and the main analysis carried baseline values forward for those who left. Read in full.
• Yancy et al. (2004). 120 adults with obesity and high blood lipids at Duke University, 24 weeks, a low-carbohydrate diet taught from Dr. Atkins' New Diet Revolution, with supplements supplied by Atkins Nutritionals, against a low-fat, reduced-calorie diet, both with group meetings. Funded by the Robert C. Atkins Foundation. Read in full from an archived copy of the publisher's web page.
• Dansinger et al. (2005). 160 adults with high blood pressure, high cholesterol or high fasting blood sugar, 1 year, Atkins, Zone, Weight Watchers or Ornish, 40 to each. The Atkins group aimed for under 20 grams of carbohydrate a day rising toward 50 grams, with 4 one-hour group meetings in the first 2 months and the diet's official cookbook; people taking diabetes pills could take part, but not people on insulin. Read in full.
• Truby et al. (2006), the BBC "diet trials." 293 adults in Britain, 6 months, Dr Atkins' New Diet Revolution, Slim-Fast, Weight Watchers or Rosemary Conley's plan, or a delayed-treatment control. People assigned to Atkins were given the book and no further advice (Truby et al., 2008). Read in full.
• McAuley et al. (2005). 96 women with insulin resistance and overweight, 24 weeks: a high-fat "Atkins Diet," a high-protein Zone diet, or a high-carbohydrate, high-fiber diet, with 8 supervised weeks of weight loss, 8 of maintenance and 8 without contact; the Atkins diet followed the guidelines in Atkins's book. Read in full.
• Gardner et al. (2007), the A TO Z trial. 311 premenopausal women with overweight or obesity in the United States, 12 months, Atkins, Zone, LEARN or Ornish, with weekly classes for 2 months, each group using its diet's book; women with diabetes were excluded. Read in full, with the published correction to its 12-month LEARN and Ornish figures.
• Shai et al. (2008), the DIRECT trial. 322 adults at a workplace in Israel, 86 percent men, including 36 with type 2 diabetes, 2 years. Its low-carbohydrate diet had no calorie limit, was based on the Atkins diet according to the authors, started at 20 grams of carbohydrate a day for 2 months and rose to at most 120 grams, with advice to choose vegetarian sources of fat and protein. It was compared with a calorie-restricted low-fat diet and a calorie-restricted Mediterranean diet, all with 18 dietitian-led group sessions and labeled cafeteria lunches. Read in full from an archived copy of the publisher's web page, captured after its 2009 correction.
• Davis et al. (2009). 105 adults with type 2 diabetes in the Bronx, 1 year, a diet "modeled after the Atkins diet" against a low-fat diet, funded partly by the Robert C. Atkins Foundation. Read in full.
• Foster et al. (2010). 307 adults with obesity at 3 U.S. centers, 2 years, guidelines from Dr. Atkins' New Diet Revolution without a copy of the book, against a low-fat, calorie-restricted diet, both with intensive group behavioral treatment led by a dietitian or psychologist. Funded by the National Institutes of Health. Read in full as the author manuscript.

Shorter studies tested the diet over 3 to 6 weeks, mostly to look at blood vessels, blood fats or mood: 20 adults over 6 weeks (Phillips et al., 2008), 18 adults who completed 3 phases of 4 weeks each of Atkins, South Beach and Ornish diets at steady weight (M. Miller et al., 2009), 24 women in a 6-week crossover trial of an Atkins diet built on vegetable oils (Haji-Ghazi Tehrani et al., 2022) and 17 active adults over 3 weeks (Butki et al., 2003). Eco-Atkins, a vegan version, was tested in 2 trials (Jenkins et al., 2009, 2014).

The searches found 5 pooled reviews that report Atkins separately: a 2020 network meta-analysis of named diets with published GRADE ratings (Ge et al., 2020), a 2015 review of commercial programs (Gudzune et al., 2015) with its companion review of blood pressure and lipids (Mehta et al., 2016), a 2014 review of 4 popular diets (Atallah et al., 2014) and a 2014 network meta-analysis of named diets (Johnston et al., 2014).

One feature of those reviews matters for reading them. The 2020 review counted as "Atkins" both trials that named Atkins and "Atkins-like" diets that did not, such as programs under 40 percent of energy from carbohydrate or programs funded by Atkins (Ge et al., 2020). The 2015 review counted 7 trials against behavioral counseling as Atkins trials. The full report of each, opened for this page, describes a diet taken from or modeled on the Atkins books, including 2 whose abstracts do not name Atkins (Gudzune et al., 2015; Shai et al., 2008; Yancy et al., 2004). Those 7 mix people with and without diabetes, so their pooled range answers a different question from this page's banner rating.

Cardiometabolic outcomes

LDL cholesterol. The clearest picture comes from the 2-year trial in the United States. LDL cholesterol rose by 7.2 mg/dL at 3 months on Atkins while it fell by 6.4 on the low-fat diet, and at 6 months it was 0.5 mg/dL above baseline on Atkins against 9.5 below on the low-fat diet. By 12 months both groups were about 8.6 mg/dL below baseline, and at 2 years the difference, 4.8 against 8.0 mg/dL lower, was not statistically significant (Foster et al., 2010). By this page's approximation from the trial's reported intervals, LDL was about 10 mg/dL higher on Atkins at 6 months, from 5 to 15, and about 3 mg/dL higher at 2 years, from 2 lower to 9 higher; these are the page's own calculations, not published intervals.

Other trials point the same way in the early months. In the insulin-resistance trial, LDL "tended to fluctuate" on the Atkins diet, and 25 percent of women on it had a rise of more than 10 percent, against 13 percent on the high-carbohydrate diet and 3 percent on the Zone diet (McAuley et al., 2005). In the BBC trial, LDL fell by 12.2 percent on the Weight Watchers and Rosemary Conley programs at 6 months but not on Atkins, although the authors saw no harmful change in lipid-based risk factors on Atkins (Morgan et al., 2009). In the 24-week Duke trial, LDL rose 1.6 mg/dL on the Atkins-based diet and fell 7.4 mg/dL on the low-fat diet, a difference that was not statistically significant (Yancy et al., 2004).

When 18 adults ate each diet for 4 weeks at steady weight, LDL rose more in the Atkins phase than in the South Beach or Ornish phases (M. Miller et al., 2009). A review of commercial programs found that at 6 months Atkins "increased LDL-c more than comparators," a difference that appeared smaller at 12 months (Mehta et al., 2016). Over 2 years in the workplace trial, LDL did not change significantly within any diet group, and the groups did not differ (Shai et al., 2008).

Against usual eating rather than a low-fat diet, the 2020 network meta-analysis estimated that LDL at 6 months was 2.75 mg/dL higher with Atkins, with an interval from 8.56 higher to 3.00 lower, low certainty by GRADE (Ge et al., 2020, supplement Table S35). These are averages. The insulin-resistance trial shows that some individuals' LDL rises a good deal more, which is why a lipid panel is the physician's tool here.

HDL cholesterol and triglycerides. These moved in the direction the company highlights. In the 2-year trial in the United States, HDL rose more on Atkins at every point, by 7.75 against 4.64 mg/dL at 2 years, about 23 percent from baseline; triglycerides fell about twice as much on Atkins over the first 6 months, a difference no longer statistically clear from 12 months on (Foster et al., 2010). The commercial-program review found higher HDL and lower triglycerides with Atkins than with comparators at 12 months, in trials it rated at high risk of bias (Mehta et al., 2016). In the BBC trial, triglycerides fell 38.2 percent on Atkins at 6 months (Morgan et al., 2009). The 2020 review rated the 6-month HDL increase against usual eating low in certainty, and reported that it was statistically clear only after adjusting for behavioral support and exercise (Ge et al., 2020).

Blood pressure. In the 2-year trial, diastolic pressure fell 2 to 3 mm Hg more on Atkins at 3 and 6 months, with no difference in systolic pressure at any point (Foster et al., 2010). Against usual eating at 6 months, the 2020 review estimated reductions of 5.14 mm Hg systolic and 3.30 mm Hg diastolic with Atkins, both moderate certainty by GRADE (Ge et al., 2020). In one head-to-head comparison, systolic pressure at 6 months was 4.5 mm Hg lower with Slim-Fast than with Atkins (Vakil et al., 2016). In the diabetes trial, blood pressure did not change in either group (Davis et al., 2009).

Blood sugar in type 2 diabetes. One trial tested an Atkins-modeled diet only in people with type 2 diabetes. At 1 year, HbA1c fell by an average of 0.02 percentage points on the Atkins-modeled diet and rose by 0.24 on the low-fat diet; the difference was not statistically clear (Davis et al., 2009). By this page's approximation the difference was 0.26 points in favor of Atkins, from 0.76 in favor of Atkins to 0.24 in favor of the low-fat diet: the interval includes an important benefit with Atkins and little or no difference, but it does not reach the 0.3 point threshold in favor of the low-fat diet. In the 2-year workplace trial, among the 36 participants with diabetes, HbA1c fell 0.9 percentage points with the Atkins-based diet and 0.4 with the low-fat diet, a difference among the 3 diet groups that was not statistically significant (Shai et al., 2008).

Insulin doses fell by an average of 10 units in the Atkins group and rose by 4 in the low-fat group, a difference that was not statistically significant (Davis et al., 2009). A company article about a study from the Albert Einstein College of Medicine, where this trial was run, says it shows that a low-fat diet "has no advantage" over a low-carbohydrate diet modeled on an Atkins program (Atkins Nutritionals, Inc., n.d.-c); the trial itself found the 2 diets similar for weight and HbA1c at 1 year.

Blood vessels and other markers. Small short trials measured how well the arteries widen, a marker linked to heart health. In 20 adults losing weight over 6 weeks, flow-mediated dilation improved on a low-fat diet and fell on an "Atkins' style diet" (Phillips et al., 2008, read as an abstract). In the 4-week crossover study at steady weight, dilation was lower after the Atkins phase than after the Ornish phase, and a later analysis of the same samples found higher levels of TMAO, a gut-derived compound studied as a heart risk marker (M. Miller et al., 2009; Park et al., 2019, read as an abstract). In a 6-week crossover trial of an Atkins diet built on vegetable oils, most cardiometabolic markers did not differ from a low-fat diet (Haji-Ghazi Tehrani et al., 2022, read as an abstract). These are markers, not heart attacks or strokes.

Kidney function. A secondary analysis of the 2-year trial in healthy adults with obesity found no noticeably harmful effects on kidney filtration, albumin in the urine or fluid balance compared with the low-fat diet; urinary calcium was about 36 percent higher at 3 and 12 months, without new kidney stones or changes in bone density (Friedman et al., 2012, read as an abstract). People with kidney disease were not studied.

Eco-Atkins. In a 4-week trial in which all food was provided, 44 of 47 adults with high cholesterol completed a vegan low-carbohydrate diet or a high-carbohydrate lacto-ovo vegetarian diet; weight loss was similar, about 4 kilograms, and LDL fell 8.1 percent more on Eco-Atkins (Jenkins et al., 2009, read as an abstract). In the 6-month follow-on trial, 39 adults started and 23 finished, 50 percent of the Eco-Atkins group and 68 percent of the comparison group. LDL fell 0.49 mmol/L more on Eco-Atkins, about 19 mg/dL, from 0.28 to 0.70 mmol/L, and weight fell 1.1 kilograms more, from 0.0 to 2.1 (Jenkins et al., 2014). This version replaces most animal foods, so these results do not apply to the company's plans.

Cancer

The searches for this page did not identify a randomized trial of the Atkins diet that measured cancer incidence or cancer outcomes. ClinicalTrials.gov lists a Duke University trial of the Atkins diet in prostate cancer that enrolled 45 people and was terminated for slow recruitment, lack of funding and the investigator's move, with no results posted (Duke University, n.d.). Research on ketogenic diets in cancer treatment is on the Ketogenic Diet page. What the trials reviewed here do not establish is any effect, good or bad, of the Atkins diet on cancer.

Body weight, as measured

Every trial reported measured body weight, in its own units. In the first 1-year trial, the Atkins group had lost 6.8 percent of body weight at 3 months against 2.7 percent, and 7.0 against 3.2 percent at 6 months, but at 12 months the difference, 4.4 against 2.5 percent, was not statistically significant (Foster et al., 2003). In the A TO Z trial, women on Atkins had lost 4.7 kilograms at 12 months, from 3.1 to 6.3, against 1.6 on Zone, 2.6 on LEARN and 2.2 on Ornish; only the difference from Zone was statistically significant (Gardner et al., 2007). By this page's approximation, the difference from LEARN, the low-fat comparison, was about 2.1 kilograms, from 0.1 to 4.1. That unadjusted approximation does not replace the trial's own analysis, which adjusted for multiple comparisons among the 4 diets and found a statistically clear difference only against Zone.

In the Boston trial, counting people who left as unchanged, the Atkins group had lost an average of 2.1 kilograms at 1 year, against 3.2 for Zone, 3.0 for Weight Watchers and 3.3 for Ornish, and weight loss was associated with how closely people said they followed their diet rather than with which diet they followed (Dansinger et al., 2005). In the BBC trial, all 4 commercial diets produced more weight and fat loss than the control group over 6 months, an average of 5.9 kilograms, and Atkins produced more loss in the first 4 weeks but "by the end was no more or less effective than the other diets" (Truby et al., 2006). In the insulin-resistance trial, women on the Atkins diet had lost 2.8 kilograms more than those on the high-carbohydrate diet (McAuley et al., 2005).

The 2-year trial in the United States compared a book-based plan with a low-fat diet. Both groups lost about 11 percent of their weight at 6 and 12 months and ended about 7 percent down at 2 years. The Atkins group had lost about 1.1 kilograms more at 3 months, a difference the authors called a strong trend at their strict significance level for secondary outcomes; at 12 months the 2 groups were within 0.1 kilogram of each other, and at 2 years the Atkins group had lost 6.3 kilograms against 7.4, a difference that was not statistically significant (Foster et al., 2010). In type 2 diabetes, weight fell faster on Atkins in the first 3 months, and both groups were 3.4 percent lighter at 1 year (Davis et al., 2009).

The DIRECT trial also belongs in this account: its published methods say the low-carbohydrate diet was based on Atkins, with adaptations favoring vegetarian sources of fat and protein. Among 322 adults followed for 2 years, mean weight loss was 4.7 kilograms with that diet, 2.9 kilograms with a low-fat diet and 4.4 kilograms with a Mediterranean diet in the intention-to-treat analysis, which carried each person's most recent weight forward. The trial included people with diabetes and substantial workplace support; it does not test the company's current plans (Shai et al., 2008). It reported its 12-month weights only in a figure and gave no separate weight result for participants without diabetes, so it is not part of this page's 12-month rating. In the 24-week Duke trial, the Atkins-based group lost 12.0 kilograms against 6.5 on the low-fat diet, 5.5 kilograms more, from 2.9 to 8.1 (Yancy et al., 2004).

Pooled reviews tell the same story. Against behavioral counseling, 7 trials counted as Atkins produced between 0.1 and 2.9 percent more weight loss at 12 months, and 1 trial against a control or education group produced 6.8 percent more at 6 months (Gudzune et al., 2015). The text of that review rates the 12-month counseling comparison at moderate risk of bias while its Table 2 rates the same comparison high, a discrepancy this page reports rather than resolves. The review's published correction, whose notice was read for this page, revised its table of adverse events, including its statement about Atkins participants, which now reports constipation; the notice does not mention the risk-of-bias labels or the weight results ("Correction: Efficacy of commercial weight-loss programs," 2015).

Against usual eating, the 2020 network meta-analysis estimated 5.46 kilograms more weight loss with Atkins at 6 months, moderate certainty by GRADE, and 3.84 kilograms at 12 months, without a certainty rating in the tables read (Ge et al., 2020, supplement Tables S35 and S37). A 2014 network meta-analysis concluded that "weight loss differences between individual named diets were small," for example 1.71 kilograms more with Atkins than with Zone at 6 months (Johnston et al., 2014, read as an abstract).

Combining the 2 trials with kilogram results against a low-fat diet at 12 months, A TO Z and the 2-year trial in the United States, gives an approximate difference of about 1 kilogram more weight lost with Atkins, with an interval from 0.4 kilogram less to 2.5 kilograms more. That is this page's own calculation, not a published meta-analysis, and it is the basis of the banner rating. Weight is reported here as a study measurement; the archive's approach to weight is explained in the review record.

This calculation combines 2 trials reporting kilograms and is not a complete meta-analysis of all eligible Atkins trials. It uses approximate, unadjusted between-group intervals; it does not replace A TO Z's multiple-comparison analysis, which found a statistically clear difference only against Zone. The other Atkins trials were checked for this question and are not combined: the first 1-year trial reported percentages, pointing the same way; the 24-week trial and the insulin-resistance trial ended before 12 months; the diabetes trial enrolled only people with type 2 diabetes; the Boston trial compared 4 named diets and admitted people taking diabetes pills; and the workplace trial included people with diabetes and gave no 12-month weight result in its text.

Mortality

The searches for this page did not identify a trial or cohort study estimating the Atkins diet's effect on survival. The trials lasted 3 weeks to 2 years and were not designed to measure deaths. In the 2-year trial, no serious cardiovascular events such as stroke or heart attack were reported, and 7 serious adverse events were listed in all; of the 3 in the Atkins group, one, "renal stones or diverticulitis," was judged possibly but not likely related to the diet, and a torn knee meniscus was judged possibly due to the prescribed exercise program (Foster et al., 2010). Those are event counts in one trial, not an estimate of safety or of an effect on death.

Eating behavior and wellbeing

In the 2-year trial, cravings for carbohydrate-rich foods, sweets and fast-food fats fell more on Atkins, while cravings for high-fat foods fell more on the low-fat diet (Martin et al., 2011). A 6-month report from the same research group found no difference between the diets in cognitive test performance (Makris et al., 2013).

In a trial of 119 adults whose low-carbohydrate diet this page could not confirm was taught from Atkins materials, but whose authors included Robert Atkins, people reported less negative mood and hunger on the low-carbohydrate diet than on a low-fat one (McClernon et al., 2007, read as an abstract). In A TO Z, women on Atkins who felt their shape and appearance had improved at 6 months regained less weight over the next 6 months, an observational finding within the trial (Moore et al., 2011, read as an abstract). The searches for this page did not identify a study measuring disordered eating in people on the Atkins diet.

Evidence from long-term prospective cohort studies

A cohort study follows people who already eat a certain way and records what happens to them. It can show that a pattern goes with an outcome; it cannot by itself show that the pattern caused it. The searches for this page did not identify a cohort study of people following the Atkins diet. Cohort studies that score how low in carbohydrate people's usual eating is measure a general pattern, not the Atkins plan, and they belong to the broader topic Low-Carbohydrate Diets. No cohort results are therefore reported here for cardiometabolic outcomes, cancer, body weight or mortality.

Highlighted studies

These 4 trials carry the most weight for this page. Each is described so a reader can judge it without opening the paper.

On a narrow screen, scroll the table sideways to see every column.

Highlighted studies for the Atkins Diet

Study	Design	Sample size	Duration	Finding	The limitation that matters
Foster et al., 2003	Randomized controlled trial, Atkins against a low-calorie, low-fat diet, minimal professional contact	63 adults with obesity	12 months	More weight lost on Atkins at 3 and 6 months, about 4 percent of body weight; the difference at 12 months, 4.4 against 2.5 percent, was not statistically significant	Small, with poor adherence and high dropout in both groups; baseline values were carried forward for those who left
Gardner et al., 2007, A TO Z	Randomized controlled trial of 4 named diets	311 premenopausal women with overweight or obesity	12 months	4.7 kilograms lost on Atkins against 1.6 to 2.6 on the other 3 diets; only the difference from Zone was statistically significant	Women only, instruction for 2 months then follow-up; the differences from LEARN and Ornish were not statistically clear after adjustment for multiple comparisons
Foster et al., 2010	Randomized controlled trial, Atkins guidelines against a low-fat diet, both with intensive group behavioral treatment	307 adults with obesity, without diabetes	2 years	About 7 percent of weight lost in both groups at 2 years, no clear difference; HDL up more on Atkins; LDL higher on Atkins at 3 and 6 months only; more constipation, bad breath, dry mouth and early hair loss	42 percent of the Atkins group missed the 2-year assessment; intensive support unlike everyday use
Davis et al., 2009	Randomized controlled trial, Atkins-modeled diet against a low-fat diet	105 adults with type 2 diabetes	12 months	Same 3.4 percent weight loss in both groups at 1 year; no clear difference in HbA1c; HDL up more on Atkins	Single center, unmasked, and the medication protocol at the start differed between groups

Head to head

Atkins has been compared directly with several named diets. In A TO Z, it was compared with Zone, LEARN and Ornish, and only the difference from Zone was statistically clear at 12 months (Gardner et al., 2007). In the Boston trial it was compared with Zone, Weight Watchers and Ornish, with similar modest results at 1 year for all 4 (Dansinger et al., 2005); the WeightWatchers page reports the same 2 trials from that program's side. In the BBC trial, Atkins, Slim-Fast, Weight Watchers and Rosemary Conley's plan did not differ significantly from one another at 6 months (Truby et al., 2006); meal replacement plans as a method are covered on the Meal Replacement Programs page.

Across all named diets, the 2020 network meta-analysis estimated that Atkins produced 1.38 kilograms more weight loss than Zone at 6 months, and described the differences among diets as "generally trivial to small" (Ge et al., 2020). The 2-year workplace trial compared its Atkins-based diet with a Mediterranean Diet and a low-fat diet; weight loss was greater with the Atkins-based and Mediterranean diets than with the low-fat diet over the 2 years (Shai et al., 2008). Trials comparing Atkins with the Ketogenic Diet, Paleo Diet or Carnivore Diet were not identified in the searches for this page.

Where the evidence is absent

The Europe PMC searches, which cover PubMed records, and the ClinicalTrials.gov searches logged for this page did not identify a study estimating the Atkins diet's effect on heart attacks, strokes, cancer or survival; a trial of the named diet that followed people beyond 2 years, apart from the 4-year follow-up of the workplace trial described in section 2; or a trial of the company's 3 current plans or of its products used as part of a plan. They found no trial of the weight-loss diet in pregnancy, breastfeeding, children or adolescents, and only medical modified Atkins research in older adults. For athletes they found one small 3-week study. They did not identify a study measuring disordered eating in people following the diet.

Nutrient research measured what people ate over 8 weeks, not blood levels of vitamins and minerals over longer periods (Gardner et al., 2010; Truby et al., 2008). ClinicalTrials.gov lists a completed 2008 to 2011 trial of the Atkins diet against a low-fat diet on inflammation, with 60 participants and no posted results, which the searches for this page did not find published (Boston Medical Center, n.d.). These are gaps in what the searches found, not findings that the diet has no effect or is safe.

5. Mechanisms

(optional reading; select the heading to open or close this section)

This section explains how the diet is thought to work in the body. You can skip it. Nothing in the coaching sections depends on it.

Established mechanisms

People eat less. The plan does not ask anyone to count calories, but people on it take in fewer. When 18 adults followed the first 2 phases from the book for 2 weeks each, their recorded intake fell from about 2,480 calories a day on their usual diet to about 1,400 in Induction and 1,560 in the next phase, and weight loss tracked the fall in intake (B. V. Miller et al., 2003, read as an abstract; that study had no comparison group).

In the BBC trial, reported energy intake fell on Atkins, as it did on the other diets (Truby et al., 2008). When the Atkins and low-fat diets came with the same intensive behavioral support in one 2-year trial, weight change was about the same, which the authors read as both approaches producing a similar energy deficit (Foster et al., 2010). In the 2-year workplace trial, reported energy intake fell by similar amounts on all 3 diets, and the authors described a similar caloric deficit in every group (Shai et al., 2008).

Ketosis in the first phase, fading later. Cutting carbohydrate to about 20 grams a day makes the liver produce ketones from fat, which can be measured in the urine. In the 2-year trial, 63 percent of the Atkins group had ketones in the urine at 3 months and 28 percent at 6 months, after which the groups did not differ, in line with the planned rise in carbohydrate (Foster et al., 2010). Nutritional ketosis is not the same as ketoacidosis, a medical emergency in which ketones build up together with acid in the blood; the difference is explained on the Ketogenic Diet page.

Water comes off first. Part of the fast early drop on the scale is water, a point the company itself makes when it lists "initial weight loss (often including water weight)" among the first changes (Atkins Nutritionals, Inc., n.d.-b). The company also warns that the early loss of water can cause lightheadedness and asks people to drink at least 8 glasses of water a day (Atkins Nutritionals, Inc., n.d.-l).

Blood fats change in a typical pattern. With less carbohydrate and more fat, triglycerides fall and HDL cholesterol rises, and LDL cholesterol tends to rise or to fall less than it does with weight loss on a low-fat diet, at least in the first months (Foster et al., 2010; Mehta et al., 2016). The authors of the 2-year trial attributed the early LDL difference to the higher fat intake on Atkins (Foster et al., 2010).

Proposed mechanisms

Researchers have proposed several reasons why people eat less on the plan: ketones may blunt appetite; protein is filling; and a short list of allowed foods simply leaves less to eat (Astrup et al., 2004, read as an abstract). These remain proposals; the trials did not test which of them matters. Self-reported hunger and cravings for sweets and starches did fall more on Atkins in some trials (Martin et al., 2011; McClernon et al., 2007), which fits the appetite explanation without proving it.

The company's central idea, that cutting carbohydrate lowers insulin and switches the body from storing fat to burning it, and that this is why the diet works, is stated on its pages as fact (Atkins Nutritionals, Inc., n.d.-a, n.d.-k). It is a proposal about mechanism. The trials do not establish that carbohydrate restriction produces a lasting weight advantage through the insulin mechanism the company proposes; comparisons differ in population, diet and support (Foster et al., 2003, 2010; Gardner et al., 2007; Shai et al., 2008). For warfarin, the authors of a 2-case report proposed that a high-protein diet raises blood albumin, which binds more of the drug and weakens its effect (Beatty et al., 2005); that too is a proposal. A proposed mechanism never supports a claim in section 4.

6. Risks, contraindications and myths

(select the heading to open or close this section)

Warnings from professional or regulatory bodies

The American Diabetes Association's 2026 Standards of Care do not name the Atkins diet, but they speak to very low carbohydrate eating plans, which include its first phase. They ask health care professionals to "maintain consistent medical oversight of individuals following very-low-carbohydrate eating plans," because insulin and other diabetes medicines may need adjusting to prevent low blood sugar and blood pressure needs monitoring. They state that such plans "are not currently recommended for individuals who are pregnant or lactating, children, people who have kidney disease, or people with or at risk for disordered eating," and that they "should be avoided" in people taking SGLT2 inhibitors "because of the potential risk of ketoacidosis" (American Diabetes Association Professional Practice Committee for Diabetes, 2026).

The company carries its own warning on every page: "The weight loss phases of the Atkins Diet should not be used by persons on dialysis," along with advice to consult a physician before beginning (Atkins Nutritionals, Inc., n.d.-a). The American Heart Association's 2023 statement on popular diets rated how well common U.S. patterns line up with its guidance; this page could open only its abstract, which names Mediterranean, DASH, pescetarian and vegetarian patterns as strongly aligned (Gardner et al., 2023). Where the statement placed very low carbohydrate patterns, including Atkins, is described from its full text on the Ketogenic Diet page.

Nutrient gaps

The first phase removes grains, legumes, starchy vegetables and nearly all fruit, so the nutrients concentrated in those foods become harder to get. In A TO Z, intakes measured by unannounced 24-hour recalls after 8 weeks showed a significant shift toward risk of inadequacy in the Atkins group for thiamin, folate, vitamin C, iron and magnesium; the other diets had their own shifts, and the Zone group's risk fell for several vitamins (Gardner et al., 2010, read as an abstract). In the BBC trial, by contrast, the authors found no evidence of micronutrient deficiency on any diet over 8 weeks, although intake of dietary fiber fell on Atkins; the Atkins group's intakes were calculated without supplements (Truby et al., 2008).

Both studies measured intake over 8 weeks, not blood levels over a year. The company suggests, but does not require, a daily iron-free multivitamin and an omega-3 supplement, and recommends psyllium husk or ground flaxseed for constipation, while stating that "a well formulated low carb diet is not associated with vitamin or mineral deficiencies" (Atkins Nutritionals, Inc., n.d.-l); that last statement is the company's claim. In the 2-year trial both groups were given a daily multivitamin (Foster et al., 2010). Whether a particular plan meets a particular person's needs is a question for a registered dietitian.

Who should not follow it without medical supervision

From the sources above: anyone taking insulin, a sulfonylurea, an SGLT2 inhibitor or blood pressure medicine (American Diabetes Association Professional Practice Committee for Diabetes, 2026), or warfarin (Beatty et al., 2005); anyone pregnant or breastfeeding; children; anyone with kidney disease, including anyone on dialysis (American Diabetes Association Professional Practice Committee for Diabetes, 2026; Atkins Nutritionals, Inc., n.d.-a); and anyone with or at risk for disordered eating. This page adds people with high LDL cholesterol, inherited high cholesterol or heart disease, because LDL rose on Atkins in the early months of the trials and steeply in some individuals (Foster et al., 2010; McAuley et al., 2005); that addition is this page's reading of the trials, and the physician decides. The special populations list in section 3 is built from this.

Medication interactions

Insulin and sulfonylureas lower blood sugar whatever is eaten, so a sudden drop in carbohydrate can cause low blood sugar unless doses change; in the diabetes trial, the protocol halved insulin and stopped sulfonylureas in the Atkins group from the start, and adjusted doses afterward by blood sugar readings (Davis et al., 2009). SGLT2 inhibitors, such as empagliflozin, dapagliflozin and canagliflozin, should not be combined with very low carbohydrate eating because of the risk of ketoacidosis (American Diabetes Association Professional Practice Committee for Diabetes, 2026). Blood pressure medicines may need review, because blood pressure can change. Warfarin: 2 patients needed 22 and 30 percent higher doses after starting high-protein, low-carbohydrate diets, a possible interaction (Beatty et al., 2005).

A coach never adjusts medication. The point of listing these is to know when to send the client back to the prescriber, and for a substantial change in eating by a client on these medicines, the client keeps the prescriber informed before the change.

Signs it is going wrong

Some physical signs call for the client's care plan, a medical assessment or emergency help. Constipation, bad breath, dry mouth, headache, tiredness and irritability are common in the first days or months and often ease (Atkins Nutritionals, Inc., n.d.-b; Foster et al., 2010); lightheadedness, constipation that persists, hair loss or pain that could be a kidney stone are reasons to see a clinician. Vomiting, abdominal pain, rapid breathing, fainting or confusion on a strict plan need urgent care, especially for anyone on an SGLT2 inhibitor or breastfeeding; a previously healthy 33-year-old woman who had followed a strict Atkins diet for 2 months developed severe ketoacidosis during a bout of flu and needed intensive care (Ullah et al., 2018).

A possible low blood sugar episode is treated first under the client's own plan, with emergency help if symptoms are severe or the person cannot manage the episode under that plan; the prescriber is told afterward. Weight the person is losing without meaning to is a reason to involve a clinician.

Eating behaviors are a separate matter. Counting carbohydrate, refusing bread at a party or eating the same few meals can have ordinary reasons: a plan the client chose, a work schedule, what the household eats, cultural practice or cost. The coach asks what the behavior is for, whether it causes distress, whether it is narrowing what the person eats beyond the plan, and whether it gets in the way of daily life. A real concern goes through the coach's own referral process, or to the client's clinician under an existing care plan. The coach does not diagnose from a behavior alone.

Myths and where they came from

Myth: "On Atkins, calories don't count. You can eat as much fat as you want."

Where it came from: the books' design, in which fatty foods are eaten freely and only carbohydrate is limited (Astrup et al., 2004), which the company repeats when it says the plan "focuses on controlling carbs rather than calories" (Atkins Nutritionals, Inc., n.d.-b). What is true: people on the plan eat less, by about 1,000 calories a day in one small study of the first phases (B. V. Miller et al., 2003), and in one 2-year trial in which a low-fat diet came with the same intensive support, weight change was about the same (Foster et al., 2010). Calories still count; the plan changes how people arrive at eating fewer.

Myth: "Atkins and keto are the same diet."

Where it came from: the first phase is ketogenic, and the company itself describes Dr. Atkins's original approach as also known as keto (Atkins Nutritionals, Inc., n.d.-h). What is true: only the start is ketogenic by design. The plans rise to 40 or 100 grams of net carbohydrate a day, and in the 2-year trial most participants no longer had urinary ketones after 6 months (Foster et al., 2010). The Ketogenic Diet page covers diets meant to stay in ketosis.

Myth: "Research has proven Dr. Atkins right."

Where it came from: the company's history page, which says decades of research "ultimately showed Dr. Atkins was right" (Atkins Nutritionals, Inc., n.d.-i), and the early trials of 2003, which found faster weight loss than with low-fat diets. What is true: in the trials against low-fat diets in adults without diabetes, the early advantage mostly faded by 12 months; of 2 trials that lasted 2 years, one found no clear difference and the other found 4.7 kilograms lost on its Atkins-based diet against 2.9 on a low-fat diet. Triglycerides and HDL improved more, LDL was higher in the early months, and the searches for this page did not identify a study estimating the diet's effect on heart attacks, strokes or survival (Foster et al., 2003, 2010; Gardner et al., 2007; Ge et al., 2020; Shai et al., 2008).

Myth: "Atkins is basically an all-meat diet."

Where it came from: the books' allowance of fatty meat, butter and high-fat dairy foods (Astrup et al., 2004). What is true: even the strictest phase requires 12 to 15 grams of net carbohydrate a day from vegetables (Atkins Nutritionals, Inc., n.d.-l), and a fully plant-based version, Eco-Atkins, has been tested (Jenkins et al., 2014). The Carnivore Diet removes plant foods altogether.

Myth: "The 5 pounds I lost in the first 2 weeks were all fat."

Where it came from: the speed of early weight loss on a very low carbohydrate start. What is true: the company itself says the first loss often includes water weight (Atkins Nutritionals, Inc., n.d.-b), and in the 2-year trial, which measured body composition by scan, the Atkins and low-fat groups lost similar amounts of fat and of lean tissue (Foster et al., 2010). Weight is a measurement here, not a goal.

7. Key terms

Net carbohydrate

The company's measure of carbohydrate that counts: total carbohydrate minus fiber, and in packaged foods minus sugar alcohols as well.

Induction

The first phase of the strictest Atkins plan, at about 20 grams of net carbohydrate a day for at least 2 weeks.

Foundation Vegetables

The company's name for the salad greens and other nonstarchy vegetables that must supply 12 to 15 grams of the day's net carbohydrate.

Personal Carb Balance

The company's term for the most net carbohydrate a person can eat each day while keeping the results they want, found by adding carbohydrate back in small steps.

Ketosis

A state in which the liver makes ketones from fat for fuel, which happens when carbohydrate intake is very low.

Ketoacidosis

A medical emergency in which ketones build up together with acid in the blood; it can occur even when blood sugar is not high, as in a reported case on a strict Atkins diet.

Modified Atkins diet

A medical diet for drug-resistant epilepsy that starts at about 10 to 15 grams of carbohydrate a day, managed by a neurology team.

Eco-Atkins

A vegan low-carbohydrate diet designed by researchers, with protein from gluten, soy and nuts.

LDL cholesterol

The cholesterol carried in low-density lipoprotein, the blood fat most closely linked to heart disease, which a physician tracks on a lipid panel.

HDL cholesterol and triglycerides

2 other blood fats on a lipid panel; on Atkins, HDL tends to rise and triglycerides to fall.

HbA1c

A blood test that reflects average blood sugar over about 3 months, used to monitor diabetes.

Sulfonylurea

A class of diabetes pills, such as glipizide, that lower blood sugar whatever a person eats and can cause low blood sugar when eating changes.

SGLT2 inhibitor

A class of diabetes medicines that should not be combined with very low carbohydrate eating because of the risk of ketoacidosis.

Network meta-analysis

A pooled analysis that compares many diets at once, using both direct comparisons from trials and indirect ones through shared comparison diets.

Missing outcome data

Measurements absent because people left a trial or skipped a visit; when many are missing, a trial's result is less certain.

8. Review questions

1. Name the 3 plans the Atkins company offers and the approximate daily net carbohydrate of each. Which part of which plan is ketogenic, and what happens to carbohydrate intake after it?
2. In the 2-year trial of an Atkins plan against a low-fat diet, both with intensive behavioral support, what happened to measured weight at 3 months, 12 months and 2 years, and what happened to LDL and HDL cholesterol? What does the trial not tell you about the company's current plans?
3. The 2020 review of named diets rated moderate certainty for weight change with Atkins at 6 months, while this page rates the 12-month evidence low. Explain why both can be true, naming the comparison, the time frame and what the review counted as Atkins.
4. A client says, "I'm starting Atkins KickStart on Monday. My doctor has me on insulin and an SGLT2 inhibitor." What would you ask, and exactly where is the referral line? What do you say if, a week later, the client describes shakiness and sweating before lunch?
5. A client tells you Atkins "proves calories don't matter." Where does that idea come from, and what do the trials show?
6. Why does the coaching scope box on this page name particular groups for medical oversight rather than apply one rule to everyone on the diet? Name the groups and the professional each needs.

9. References

American Diabetes Association Professional Practice Committee for Diabetes. (2026). 5. Facilitating positive health behaviors and well-being to improve health outcomes: Standards of Care in Diabetes-2026. Diabetes Care, 49(Suppl. 1), S89-S131. https://doi.org/10.2337/dc26-S005

Alhassan, S., Kim, S., Bersamin, A., King, A. C., & Gardner, C. D. (2008). Dietary adherence and weight loss success among overweight women: Results from the A TO Z weight loss study. International Journal of Obesity, 32(6), 985-991. https://doi.org/10.1038/ijo.2008.8

Astrup, A., Meinert Larsen, T., & Harper, A. (2004). Atkins and other low-carbohydrate diets: Hoax or an effective tool for weight loss? The Lancet, 364(9437), 897-899. https://doi.org/10.1016/S0140-6736(04)16986-9

Atallah, R., Filion, K. B., Wakil, S. M., Genest, J., Joseph, L., Poirier, P., Rinfret, S., Schiffrin, E. L., & Eisenberg, M. J. (2014). Long-term effects of 4 popular diets on weight loss and cardiovascular risk factors: A systematic review of randomized controlled trials. Circulation: Cardiovascular Quality and Outcomes, 7(6), 815-827. https://doi.org/10.1161/CIRCOUTCOMES.113.000723

Atkins Nutritionals, Inc. (n.d.-a). Atkins diet plans: Atkins 100, 40 & 20. www.atkins.com/discover-atkins/diet-plans

Atkins Nutritionals, Inc. (n.d.-b). Atkins Kickstart FAQs. www.atkins.com/expertise/atkins-20-faqs

Atkins Nutritionals, Inc. (n.d.-c). Atkins low carb diet for diabetics. www.atkins.com/expertise/atkins-for-diabetics

Atkins Nutritionals, Inc. (n.d.-d). Atkins online store. shop.atkins.com

Atkins Nutritionals, Inc. (n.d.-e). Classic shakes. Atkins online store. shop.atkins.com/collections/classic-shakes

Atkins Nutritionals, Inc. (n.d.-f). Frequently asked questions. www.atkins.com/faqs

Atkins Nutritionals, Inc. (n.d.-g). GLP-1 friendly. www.atkins.com/discover-atkins/weight-loss-medications

Atkins Nutritionals, Inc. (n.d.-h). A low-carb philosophy for wellness. www.atkins.com/discover-atkins/philosophy

Atkins Nutritionals, Inc. (n.d.-i). Meet the Atkins diet founder and discover our mission. www.atkins.com/discover-atkins/our-story

Atkins Nutritionals, Inc. (n.d.-j). Phase 1: Induction. www.atkins.com/expertise/phase-1-induction

Atkins Nutritionals, Inc. (n.d.-k). Re-introducing Atkins 20. www.atkins.com/expertise/re-introducing-atkins-20

Atkins Nutritionals, Inc. (n.d.-l). Rules of Induction: Achieve ketosis with low carbs. www.atkins.com/expertise/the-rules-of-induction

Beatty, S. J., Mehta, B. H., & Rodis, J. L. (2005). Decreased warfarin effect after initiation of high-protein, low-carbohydrate diets. Annals of Pharmacotherapy, 39(4), 744-747. https://doi.org/10.1345/aph.1E454

Boston Medical Center. (n.d.). Effects of the Atkins diet versus a low fat diet on inflammation (Identifier NCT00993278) [Clinical trial registration]. ClinicalTrials.gov. clinicaltrials.gov/study/NCT00993278

Buchholz, A., Deme, P., Betz, J. F., Brandt, J., Haughey, N., & Cervenka, M. C. (2024). A randomized feasibility trial of the modified Atkins diet in older adults with mild cognitive impairment due to Alzheimer's disease. Frontiers in Endocrinology, 15, Article 1182519. https://doi.org/10.3389/fendo.2024.1182519

Butki, B. D., Baumstark, J., & Driver, S. (2003). Effects of a carbohydrate-restricted diet on affective responses to acute exercise among physically active participants. Perceptual and Motor Skills, 96(2), 607-615. https://doi.org/10.2466/pms.2003.96.2.607

Correction: Efficacy of commercial weight-loss programs. (2015). Annals of Internal Medicine, 162(10), 739-740. https://doi.org/10.7326/L15-5097

A critique of low-carbohydrate ketogenic weight reduction regimens: A review of Dr. Atkins' diet revolution. (1973). JAMA, 224(10), 1415-1419. https://doi.org/10.1001/jama.1973.03220240055018

Dansinger, M. L., Gleason, J. A., Griffith, J. L., Selker, H. P., & Schaefer, E. J. (2005). Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: A randomized trial. JAMA, 293(1), 43-53. https://doi.org/10.1001/jama.293.1.43

Davis, N. J., Tomuta, N., Schechter, C., Isasi, C. R., Segal-Isaacson, C. J., Stein, D., Zonszein, J., & Wylie-Rosett, J. (2009). Comparative study of the effects of a 1-year dietary intervention of a low-carbohydrate diet versus a low-fat diet on weight and glycemic control in type 2 diabetes. Diabetes Care, 32(7), 1147-1152. https://doi.org/10.2337/dc08-2108

Duke University. (n.d.). Atkins diet and prostate cancer clinical trial (Identifier NCT00932672) [Clinical trial registration]. ClinicalTrials.gov. clinicaltrials.gov/study/NCT00932672

Finney Rutten, L. J., Lazarus Yaroch, A., Colón-Ramos, U., & Atienza, A. A. (2008). Awareness, use, and perceptions of low-carbohydrate diets. Preventing Chronic Disease, 5(4), Article A130. www.cdc.gov/pcd/issues/2008/oct/07_0118.htm

Foster, G. D., Wyatt, H. R., Hill, J. O., McGuckin, B. G., Brill, C., Mohammed, B. S., Szapary, P. O., Rader, D. J., Edman, J. S., & Klein, S. (2003). A randomized trial of a low-carbohydrate diet for obesity. The New England Journal of Medicine, 348(21), 2082-2090. https://doi.org/10.1056/NEJMoa022207

Foster, G. D., Wyatt, H. R., Hill, J. O., Makris, A. P., Rosenbaum, D. L., Brill, C., Stein, R. I., Mohammed, B. S., Miller, B., Rader, D. J., Zemel, B., Wadden, T. A., Tenhave, T., Newcomb, C. W., & Klein, S. (2010). Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet: A randomized trial. Annals of Internal Medicine, 153(3), 147-157. https://doi.org/10.7326/0003-4819-153-3-201008030-00005

Friedman, A. N., Ogden, L. G., Foster, G. D., Klein, S., Stein, R., Miller, B., Hill, J. O., Brill, C., Bailer, B., Rosenbaum, D. R., & Wyatt, H. R. (2012). Comparative effects of low-carbohydrate high-protein versus low-fat diets on the kidney. Clinical Journal of the American Society of Nephrology, 7(7), 1103-1111. https://doi.org/10.2215/CJN.11741111

Gardner, C. D., Kiazand, A., Alhassan, S., Kim, S., Stafford, R. S., Balise, R. R., Kraemer, H. C., & King, A. C. (2007). Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: The A TO Z Weight Loss Study: A randomized trial. JAMA, 297(9), 969-977. https://doi.org/10.1001/jama.297.9.969

Gardner, C. D., Kim, S., Bersamin, A., Dopler-Nelson, M., Otten, J., Oelrich, B., & Cherin, R. (2010). Micronutrient quality of weight-loss diets that focus on macronutrients: Results from the A TO Z study. The American Journal of Clinical Nutrition, 92(2), 304-312. https://doi.org/10.3945/ajcn.2010.29468

Gardner, C. D., Vadiveloo, M. K., Petersen, K. S., Anderson, C. A. M., Springfield, S., Van Horn, L., Khera, A., Lamendola, C., Mayo, S. M., Joseph, J. J., & American Heart Association Council on Lifestyle and Cardiometabolic Health. (2023). Popular dietary patterns: Alignment with American Heart Association 2021 dietary guidance: A scientific statement from the American Heart Association. Circulation, 147(22), 1715-1730. https://doi.org/10.1161/CIR.0000000000001146

Ge, L., Sadeghirad, B., Ball, G. D. C., da Costa, B. R., Hitchcock, C. L., Svendrovski, A., Kiflen, R., Quadri, K., Kwon, H. Y., Karamouzian, M., Adams-Webber, T., Ahmed, W., Damanhoury, S., Zeraatkar, D., Nikolakopoulou, A., Tsuyuki, R. T., Tian, J., Yang, K., Guyatt, G. H., & Johnston, B. C. (2020). Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: Systematic review and network meta-analysis of randomised trials. BMJ, 369, Article m696. https://doi.org/10.1136/bmj.m696. A correction was published (BMJ, 370, Article m3095, https://doi.org/10.1136/bmj.m3095); it concerns the estimates for macronutrient patterns, not the named-diet tables used on this page.

Gudzune, K. A., Doshi, R. S., Mehta, A. K., Chaudhry, Z. W., Jacobs, D. K., Vakil, R. M., Lee, C. J., Bleich, S. N., & Clark, J. M. (2015). Efficacy of commercial weight-loss programs: An updated systematic review. Annals of Internal Medicine, 162(7), 501-512. https://doi.org/10.7326/M14-2238

Haji-Ghazi Tehrani, L., Mousavi, S. N., Chiti, H., & Afshar, D. (2022). Effect of Atkins versus a low-fat diet on gut microbiota, and cardiometabolic markers in obese women following an energy-restricted diet: Randomized, crossover trial. Nutrition, Metabolism and Cardiovascular Diseases, 32(7), 1734-1741. https://doi.org/10.1016/j.numecd.2022.04.007

Jenkins, D. J. A., Wong, J. M. W., Kendall, C. W. C., Esfahani, A., Ng, V. W. Y., Leong, T. C. K., Faulkner, D. A., Vidgen, E., Greaves, K. A., Paul, G., & Singer, W. (2009). The effect of a plant-based low-carbohydrate ("Eco-Atkins") diet on body weight and blood lipid concentrations in hyperlipidemic subjects. Archives of Internal Medicine, 169(11), 1046-1054. https://doi.org/10.1001/archinternmed.2009.115

Jenkins, D. J. A., Wong, J. M. W., Kendall, C. W. C., Esfahani, A., Ng, V. W. Y., Leong, T. C. K., Faulkner, D. A., Vidgen, E., Paul, G., Mukherjea, R., Krul, E. S., & Singer, W. (2014). Effect of a 6-month vegan low-carbohydrate ("Eco-Atkins") diet on cardiovascular risk factors and body weight in hyperlipidaemic adults: A randomised controlled trial. BMJ Open, 4(2), Article e003505. https://doi.org/10.1136/bmjopen-2013-003505

Johnston, B. C., Kanters, S., Bandayrel, K., Wu, P., Naji, F., Siemieniuk, R. A., Ball, G. D. C., Busse, J. W., Thorlund, K., Guyatt, G., Jansen, J. P., & Mills, E. J. (2014). Comparison of weight loss among named diet programs in overweight and obese adults: A meta-analysis. JAMA, 312(9), 923-933. https://doi.org/10.1001/jama.2014.10397

Kossoff, E. H., Zupec-Kania, B. A., Auvin, S., Ballaban-Gil, K. R., Bergqvist, A. G. C., Blackford, R., Buchhalter, J. R., Caraballo, R. H., Cross, J. H., Dahlin, M. G., Donner, E. J., Guzel, O., Jehle, R. S., Klepper, J., Kang, H. C., Lambrechts, D. A., Liu, Y. M. C., Nathan, J. K., Nordli, D. R., . . . Wirrell, E. C. (2018). Optimal clinical management of children receiving dietary therapies for epilepsy: Updated recommendations of the International Ketogenic Diet Study Group. Epilepsia Open, 3(2), 175-192. https://doi.org/10.1002/epi4.12225

Lean, M. E., & Lara, J. (2004). Is Atkins dead (again)? Nutrition, Metabolism and Cardiovascular Diseases, 14(2), 61-65. https://doi.org/10.1016/S0939-4753(04)80011-5

Makris, A., Darcey, V. L., Rosenbaum, D. L., Komaroff, E., Vander Veur, S. S., Collins, B. N., Klein, S., Wyatt, H. R., & Foster, G. D. (2013). Similar effects on cognitive performance during high- and low-carbohydrate obesity treatment. Nutrition & Diabetes, 3, Article e89. https://doi.org/10.1038/nutd.2013.29

Martin, C. K., Rosenbaum, D., Han, H., Geiselman, P. J., Wyatt, H. R., Hill, J. O., Brill, C., Bailer, B., Miller, B. V., Stein, R., Klein, S., & Foster, G. D. (2011). Change in food cravings, food preferences, and appetite during a low-carbohydrate and low-fat diet. Obesity, 19(10), 1963-1970. https://doi.org/10.1038/oby.2011.62

McAuley, K. A., Hopkins, C. M., Smith, K. J., McLay, R. T., Williams, S. M., Taylor, R. W., & Mann, J. I. (2005). Comparison of high-fat and high-protein diets with a high-carbohydrate diet in insulin-resistant obese women. Diabetologia, 48(1), 8-16. https://doi.org/10.1007/s00125-004-1603-4

McClernon, F. J., Yancy, W. S., Eberstein, J. A., Atkins, R. C., & Westman, E. C. (2007). The effects of a low-carbohydrate ketogenic diet and a low-fat diet on mood, hunger, and other self-reported symptoms. Obesity, 15(1), 182-187. https://doi.org/10.1038/oby.2007.516

Mehta, A. K., Doshi, R. S., Chaudhry, Z. W., Jacobs, D. K., Vakil, R. M., Lee, C. J., Bleich, S. N., Clark, J. M., & Gudzune, K. A. (2016). Benefits of commercial weight-loss programs on blood pressure and lipids: A systematic review. Preventive Medicine, 90, 86-99. https://doi.org/10.1016/j.ypmed.2016.06.028

Miller, B. V., Bertino, J. S., Reed, R. G., Burrington, C. M., Davidson, L. K., Green, A., Gartung, A. M., & Nafziger, A. N. (2003). An evaluation of the Atkins' diet. Metabolic Syndrome and Related Disorders, 1(4), 299-309. https://doi.org/10.1089/1540419031361426

Miller, M., Beach, V., Sorkin, J. D., Mangano, C., Dobmeier, C., Novacic, D., Rhyne, J., & Vogel, R. A. (2009). Comparative effects of three popular diets on lipids, endothelial function, and C-reactive protein during weight maintenance. Journal of the American Dietetic Association, 109(4), 713-717. https://doi.org/10.1016/j.jada.2008.12.023

Moore, S. D., King, A. C., Kiernan, M., & Gardner, C. D. (2011). Outcome expectations and realizations as predictors of weight regain among dieters. Eating Behaviors, 12(1), 60-63. https://doi.org/10.1016/j.eatbeh.2010.08.007

Morgan, L. M., Griffin, B. A., Millward, D. J., DeLooy, A., Fox, K. R., Baic, S., Bonham, M. P., Wallace, J. M., MacDonald, I., Taylor, M. A., & Truby, H. (2009). Comparison of the effects of four commercially available weight-loss programmes on lipid-based cardiovascular risk factors. Public Health Nutrition, 12(6), 799-807. https://doi.org/10.1017/S1368980008003236

Park, J. E., Miller, M., Rhyne, J., Wang, Z., & Hazen, S. L. (2019). Differential effect of short-term popular diets on TMAO and other cardio-metabolic risk markers. Nutrition, Metabolism and Cardiovascular Diseases, 29(5), 513-517. https://doi.org/10.1016/j.numecd.2019.02.003

Phillips, S. A., Jurva, J. W., Syed, A. Q., Syed, A. Q., Kulinski, J. P., Pleuss, J., Hoffmann, R. G., & Gutterman, D. D. (2008). Benefit of low-fat over low-carbohydrate diet on endothelial health in obesity. Hypertension, 51(2), 376-382. https://doi.org/10.1161/HYPERTENSIONAHA.107.101824

Schwarzfuchs, D., Golan, R., & Shai, I. (2012). Four-year follow-up after two-year dietary interventions. The New England Journal of Medicine, 367(14), 1373-1374. https://doi.org/10.1056/NEJMc1204792

Shai, I., Schwarzfuchs, D., Henkin, Y., Shahar, D. R., Witkow, S., Greenberg, I., Golan, R., Fraser, D., Bolotin, A., Vardi, H., Tangi-Rozental, O., Zuk-Ramot, R., Sarusi, B., Brickner, D., Schwartz, Z., Sheiner, E., Marko, R., Katorza, E., Thiery, J., . . . Stampfer, M. J. (2008). Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. The New England Journal of Medicine, 359(3), 229-241. https://doi.org/10.1056/NEJMoa0708681

The Simply Good Foods Company. (2025). Annual report on Form 10-K for the fiscal year ended August 30, 2025. U.S. Securities and Exchange Commission. www.sec.gov/Archives/edgar/data/1702744/000170274425000046/atk-20250830.htm

The Simply Good Foods Company. (2026, July 9). The Simply Good Foods Company reports fiscal third quarter 2026 financial results and updates fiscal year 2026 outlook [Press release]. Exhibit 99.1 to Form 8-K, U.S. Securities and Exchange Commission. www.sec.gov/Archives/edgar/data/1702744/000170274426000021/a991_pressreleasexq3x2026.htm

Sondike, S. B., Copperman, N., & Jacobson, M. S. (2003). Effects of a low-carbohydrate diet on weight loss and cardiovascular risk factors in overweight adolescents. The Journal of Pediatrics, 142(3), 253-258. https://doi.org/10.1067/mpd.2003.4

Truby, H., Baic, S., deLooy, A., Fox, K. R., Livingstone, M. B. E., Logan, C. M., Macdonald, I. A., Morgan, L. M., Taylor, M. A., & Millward, D. J. (2006). Randomised controlled trial of four commercial weight loss programmes in the UK: Initial findings from the BBC "diet trials." BMJ, 332(7553), 1309-1314. https://doi.org/10.1136/bmj.38833.411204.80

Truby, H., Hiscutt, R., Herriot, A. M., Stanley, M., Delooy, A., Fox, K. R., Baic, S., Robson, P. J., Macdonald, I., Taylor, M. A., Ware, R., Logan, C., & Livingstone, M. B. E. (2008). Commercial weight loss diets meet nutrient requirements in free living adults over 8 weeks: A randomised controlled weight loss trial. Nutrition Journal, 7, Article 25. https://doi.org/10.1186/1475-2891-7-25

Ullah, W., Hamid, M., Mohammad Ammar Abdullah, H., Ur Rashid, M., & Inayat, F. (2018). Another "D" in MUDPILES? A review of diet-associated nondiabetic ketoacidosis. Journal of Investigative Medicine High Impact Case Reports, 6, Article 2324709618796261. https://doi.org/10.1177/2324709618796261

Vakil, R. M., Doshi, R. S., Mehta, A. K., Chaudhry, Z. W., Jacobs, D. K., Lee, C. J., Bleich, S. N., Clark, J. M., & Gudzune, K. A. (2016). Direct comparisons of commercial weight-loss programs on weight, waist circumference, and blood pressure: A systematic review. BMC Public Health, 16, Article 460. https://doi.org/10.1186/s12889-016-3112-z

Yancy, W. S., Olsen, M. K., Guyton, J. R., Bakst, R. P., & Westman, E. C. (2004). A low-carbohydrate, ketogenic diet versus a low-fat diet to treat obesity and hyperlipidemia: A randomized, controlled trial. Annals of Internal Medicine, 140(10), 769-777. https://doi.org/10.7326/0003-4819-140-10-200405180-00006

Evidence rating and review record

Each row identifies the method, source, outcome or recommendation, and comparison being rated. Ratings from different tools are not interchangeable. The source is either a named published review or this page's own judgment. The rating in the banner is for this diet's main claimed outcome or recommendation, and the banner names the tool that produced it. A high rating means the research is solid; it does not mean the diet is right for everyone, and it does not mean a coach should recommend it.

Rows rated with GRADE use the same 4-level scale as the clinical guidelines you will meet in practice. High means further research is very unlikely to change the conclusion. Moderate means further research may change it. Low means further research is likely to change it. Very low means the conclusion is uncertain. GRADE rates each outcome separately, so a diet can be high for one outcome and very low for another.

For the Atkins diet, 5 rows are carried exactly as published by the 2020 network meta-analysis of named diets, whose "Atkins" includes Atkins-like diets and whose comparison is usual eating. The other 7 rated rows are this page's own judgments from trials that named Atkins or used its books, each naming its intervention, comparison, population, outcome, time point and threshold. Thresholds are analytical boundaries for reading a measurement, not goals for a client. Several intervals are this page's approximations from reported group results and are labeled as such. Not rated means no adequate body of evidence for that question; it does not mean no effect.

On a narrow screen, scroll the table sideways to see every column.

Evidence ratings, their sources and reasons

Outcome	Certainty	Who rated it, and for which comparison	Why it is rated this way
Measured body weight at 12 months, Atkins against a low-fat, reduced-calorie diet (the banner)	Low, for a difference that may be small or absent	GRADE, this page's own judgment. Atkins taught from the books in trials published 2003 to 2010 (Foster et al., 2003; Gardner et al., 2007, the LEARN comparison; Foster et al., 2010) against a low-fat, reduced-calorie diet with similar contact, adults with overweight or obesity without diabetes, 12 months. The trial inventory for this question was rechecked against the 7 trials a 2015 review counted as Atkins; the others are left out for their population, duration or comparison, as section 4 explains (Gudzune et al., 2015). Threshold: 1 kilogram, an analytical measurement boundary used across this archive's commercial-program pages, not a client goal; the 2020 review used 2 kilograms as its importance threshold.	Randomized trials start high. Lowered 1 level for risk of bias: weight was measured on scales, but participants knew their diet and directed their own eating, and 12-month weights were missing for about a quarter of the 2-year trial, for 12 and 24 percent of the A TO Z Atkins and LEARN groups, and for 39 and 43 percent of the first trial's groups, whose main analysis carried baseline values forward, so differential dropout could shift the estimates; the 2-year trial's mixed-model and sensitivity analyses reduce, but do not remove, that concern. Not lowered for inconsistency: the trials point the same way or show no difference, from about 0 to 2 kilograms; this page's 2-trial combination has an I-squared of about 50 percent with overlapping intervals. Not lowered for indirectness for the book-based versions and adults named; the company's current plans were not tested and are outside this question. Lowered 1 level for imprecision: this page's approximate combination of the 2 kilogram-reporting trials is about 1.05 kilograms more weight lost with Atkins, from 0.36 kilograms less to 2.47 more, which crosses both no difference and the 1 kilogram boundary. The combination uses approximate, unadjusted intervals and does not replace the A TO Z trial's analysis adjusted for multiple comparisons, which found a statistically clear difference only against Zone. Publication bias not lowered; too few trials to test, and the 2015 review's range across 7 trials counted as Atkins, 0.1 to 2.9 percent, is consistent. Nothing raises the rating. High minus 2 levels is Low. The 3 trial reports were read in full, so the rating is no longer marked provisional.
Measured body weight at 2 years, Atkins against a low-fat diet, both with intensive behavioral treatment	Low, for no clear difference; an important difference either way is not excluded	GRADE, this page's own judgment. Foster et al. (2010): Atkins guidelines against a low-fat, calorie-restricted diet, both with group behavioral treatment, 307 adults with obesity without diabetes, 2 years. Threshold: 1 kilogram, as in the row above. This row rates that trial only; the 2-year workplace trial differs in population, diet and support and is described in section 4, not combined here.	Randomized trial starts high. Lowered 1 level for risk of bias: 42 percent of the Atkins group and 32 percent of the low-fat group missed the 2-year assessment, and participants knew their diet; the trial's mixed-model analysis and sensitivity analyses did not change its conclusion. Inconsistency cannot be assessed from one trial. Not lowered for indirectness for this version with intensive support. Lowered 1 level for imprecision: by this page's approximation from the reported group intervals, the Atkins group lost about 1.03 kilograms less, from 1.41 more to 3.47 less, crossing the 1 kilogram boundary in both directions. Publication bias not detected. Nothing raises the rating. High minus 2 levels is Low.
LDL cholesterol at 6 months, Atkins against a low-fat diet	Moderate, for higher LDL on Atkins	GRADE, this page's own judgment. Foster et al. (2010), supported by Yancy et al. (2004), McAuley et al. (2005), Morgan et al. (2009) and Mehta et al. (2016). Atkins against low-fat or higher-carbohydrate weight-loss diets, adults with overweight or obesity, 6 months. Threshold: 5 mg/dL, about 0.13 mmol/L, the importance threshold the 2020 review of named diets specified in advance (Ge et al., 2020).	Randomized trials start high. Not lowered for risk of bias: LDL was measured in a standardized laboratory, missing data at 6 months were 16 and 12 percent and were handled by a mixed model, and unmasked participants are not a route to bias in a laboratory value by themselves; the supporting trials have higher risk of bias but point the same way. Not lowered for inconsistency: every trial described found LDL higher, or falling less, on Atkins in the early months. Not lowered for indirectness. Lowered 1 level for imprecision: this page's approximation of the 6-month difference in the 2-year trial is about 10.1 mg/dL higher on Atkins, from 5.0 to 15.1, so its lower limit touches the 5 mg/dL threshold, a judgment sensitive to rounding. Publication bias not detected. Nothing raises the rating. High minus 1 level is Moderate. These are averages; some individuals' LDL rose far more.
LDL cholesterol at 2 years, Atkins against a low-fat diet, both with intensive behavioral treatment	Low, for no clear difference	GRADE, this page's own judgment. Foster et al. (2010), 307 adults, 2 years. Threshold: 5 mg/dL, as in the row above.	Randomized trial starts high. Lowered 1 level for risk of bias: missing data of 42 and 32 percent at 2 years. Inconsistency cannot be assessed from one trial. Not lowered for indirectness. Lowered 1 level for imprecision: by this page's approximation, LDL was about 3.2 mg/dL higher on Atkins, from 2.3 lower to 8.8 higher, crossing both no difference and the 5 mg/dL threshold. Publication bias not detected. Nothing raises the rating. High minus 2 levels is Low.
HbA1c at 12 months in adults with type 2 diabetes, Atkins-modeled diet against a low-fat diet	Low; the interval includes an important benefit with Atkins and little or no difference	GRADE, this page's own judgment. Davis et al. (2009): 105 adults with type 2 diabetes, 1 year. Thresholds: 0.3 and 0.5 percentage points, the boundaries used for HbA1c on this archive's commercial-program pages.	Randomized trial starts high. Lowered 1 level for risk of bias: participants and staff knew the assignments, 19 percent of HbA1c values were missing at 12 months, and the medication protocol at randomization differed between groups, halving insulin and stopping sulfonylureas in the Atkins group, a cointervention that could move HbA1c in either direction. Inconsistency cannot be assessed from one trial. Not lowered for indirectness for this Atkins-modeled diet and population. Lowered 1 level for imprecision: by this page's approximation from the reported means and standard deviations, the difference was about 0.26 points in favor of Atkins, from 0.76 in favor of Atkins to 0.24 in favor of the low-fat diet, crossing no difference and the benefit thresholds of 0.3 and 0.5 points; it does not reach the corresponding thresholds favoring low fat. Publication bias not detected. Nothing raises the rating. High minus 2 levels is Low.
Minor symptoms in the first 3 months, such as constipation, bad breath and dry mouth, Atkins against a low-fat diet	Moderate, for more frequent symptoms on Atkins	GRADE, this page's own judgment. Foster et al. (2010), Table 3, 307 adults, 3 months; supported by Gudzune et al. (2015), which reports constipation among Atkins participants. Threshold: a difference of 10 percentage points in the share of people reporting a symptom, this page's analytical boundary.	Randomized trial starts high. Lowered 1 level for risk of bias: symptoms were self-reported by participants who knew their diet, which could raise reporting in either group, and some data were missing. Inconsistency cannot be assessed from one trial with full data. Not lowered for indirectness. Not lowered for imprecision: at 3 months, 63 against 39 percent reported constipation, 64 against 37 percent bad breath and 48 against 25 percent dry mouth; by this page's approximation from the reported intervals, the smallest of these differences runs from about 10 to 36 percentage points. Publication bias not detected. Nothing raises the rating. High minus 1 level is Moderate. Hair loss was more often reported at 6 months, 45 against 21 percent, and constipation stayed more common through 2 years.
LDL cholesterol at 6 months, Eco-Atkins against a high-carbohydrate lacto-ovo vegetarian diet	Low, for lower LDL on Eco-Atkins	GRADE, this page's own judgment. Jenkins et al. (2014): 39 adults with high cholesterol, 6 months after a 1-month feeding phase. Threshold: about 0.13 mmol/L, as in the LDL rows above.	Randomized trial starts high. Lowered 2 levels for very serious risk of bias: only 23 of 39 participants completed, 50 percent of the Eco-Atkins group against 68 percent of the comparison group, so missing data were large and unequal. Inconsistency cannot be assessed from one 6-month trial, although the earlier 4-week trial pointed the same way. Not lowered for indirectness for this named research diet; it does not apply to the company's plans. Not lowered for imprecision: the difference was 0.49 mmol/L lower, from 0.28 to 0.70, beyond the threshold. Publication bias not detected. Nothing raises the rating. High minus 2 levels is Low.
Measured body weight at 6 months, Atkins against usual diet	Moderate	GRADE, published: Ge et al. (2020), network meta-analysis, supplement Table S35. Atkins, a node that also includes Atkins-like diets under 40 percent of energy from carbohydrate or funded by Atkins, against usual diet, adults with overweight or obesity, 6 months. Estimate: 5.46 kilograms more weight loss, credible interval 4.19 to 6.75.	Carried exactly as published. The review rated the direct evidence, 1 trial of 80 people, low, and the network estimate, which draws mostly on trials comparing Atkins and Atkins-like diets with low-fat diets, moderate (Table S29). The review's 12-month estimate, 3.84 kilograms, from 2.10 to 5.59, carries no certainty rating in the tables read, and this page does not assign one.
Systolic blood pressure at 6 months, Atkins against usual diet	Moderate	GRADE, published: Ge et al. (2020), network meta-analysis, supplement Table S35. Atkins, a node that also includes Atkins-like diets under 40 percent of energy from carbohydrate or funded by Atkins, against usual diet, adults with overweight or obesity, 6 months. Estimate: 5.14 mm Hg greater reduction, from 2.78 to 7.57.	Carried exactly as published.
Diastolic blood pressure at 6 months, Atkins against usual diet	Moderate	GRADE, published: Ge et al. (2020), network meta-analysis, supplement Table S35. Atkins, a node that also includes Atkins-like diets under 40 percent of energy from carbohydrate or funded by Atkins, against usual diet, adults with overweight or obesity, 6 months. Estimate: 3.30 mm Hg greater reduction, from 1.67 to 4.99.	Carried exactly as published.
LDL cholesterol at 6 months, Atkins against usual diet	Low	GRADE, published: Ge et al. (2020), network meta-analysis, supplement Table S35. Atkins, a node that also includes Atkins-like diets under 40 percent of energy from carbohydrate or funded by Atkins, against usual diet, adults with overweight or obesity, 6 months. Estimate: 2.75 mg/dL higher with Atkins, from 8.56 higher to 3.00 lower.	Carried exactly as published. The review lists Atkins among the diets that "may be among the least effective" for lowering LDL.
HDL cholesterol at 6 months, Atkins against usual diet	Low	GRADE, published: Ge et al. (2020), network meta-analysis, supplement Table S35. Atkins, a node that also includes Atkins-like diets under 40 percent of energy from carbohydrate or funded by Atkins, against usual diet, adults with overweight or obesity, 6 months. Estimate: 3.41 mg/dL greater increase, from 0.83 to 5.75.	Carried exactly as published. The review notes that the Atkins result was statistically significant only after adjusting for behavioral support and exercise.
Heart attacks, strokes, cancer and death	Not rated	This page's own judgment. Atkins against any comparison.	The Europe PMC and ClinicalTrials.gov searches for this page did not identify a trial or cohort study estimating the diet's effect on these outcomes; the 2-year trial's report of no serious cardiovascular events is an event count, not an estimate. This is an absence of evidence in those searches, not a finding of no effect or of safety.
Onset or return of disordered eating	Not rated	This page's own judgment. People following Atkins against people who are not, including people with a history of disordered eating.	The searches for this page did not identify a study measuring this outcome. The American Diabetes Association's caution and the strictness of the first phase are reasons for care, not evidence on the outcome.
Health effects in pregnancy, breastfeeding, children and adolescents	Not rated	This page's own judgment. The company's plans against usual eating in these groups.	The searches for this page found no trial of the weight-loss diet in these groups. The medical modified Atkins diet for epilepsy and adolescent trials at ketogenic carbohydrate levels are different questions, covered on the Ketogenic Diet page. Not rated does not mean safe or harmful.

How this archive talks about weight. This page reports what studies measured, including body weight, and does not treat weight change as a goal or as a measure of a diet's success. Weight a person loses without meaning to can be a sign of a health problem, and where it is, the page names it as a reason to see a clinician. People are described the way the study described them.

Last reviewed: Reviewed and approved by James Peth, MS, MPH, PhD, on October 21, 2026, after a combined final review of the fifth batch of 5 archive pages, the repairs it asked for and a targeted recheck. Written October 19, 2026. What changed: First version. The judgments in the table, apart from the 5 rows carried from a published review, are this page's own, assigned from the evidence. Some sources could be read only as abstracts or author manuscripts, and the page says so where each is used. Company prices, plans and financial figures are a snapshot from the company's own pages and filings as read on October 19, 2026, with the store prices rechecked and unchanged on October 21, 2026, and can change.

What changed in this revision: The 2-year DIRECT workplace trial and a 24-week trial at Duke University were added as Atkins trials, because their full reports say the diet was based on Atkins or taught from its book, and a 4-year follow-up of the workplace trial was added. The summaries of the 2-year evidence, the head-to-head comparisons, the mechanisms and the myth answers were rewritten to match both 2-year trials. The type 2 diabetes row now states which thresholds its interval reaches. The banner row's calculation now states its limits, and its provisional mark was removed after the original trial reports were read and its trial list was rechecked. The footprint section now points to the Ketogenic Diet page instead of repeating its figures. Several sources first read as abstracts were read in full.

What changed after the targeted recheck: The certainty label in the type 2 diabetes row now says the interval includes an important benefit with Atkins and little or no difference, matching that row's explanation. The rating stays Low.

Next scheduled review: Each year, because the company renames its plans and changes its products and prices, and its parent company reported falling Atkins sales in 2026. The American Diabetes Association updates its Standards of Care every year, and its statements on very low carbohydrate eating should be rechecked first. Pages built on annual guidance are rechecked each year.

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Diet Reference Archive | One James

Prepared by James Peth, MS, MPH, PhD

© 2026–2027 One James. All rights reserved.

This page is for education and coaching practice. It is not medical or dietary advice.