Atkins Diet


The Atkins diet, also known as the Atkins Nutritional Approach, is a low-carbohydrate, high-fat (LCHF) diet regimen. It emphasizes meat, cheese, eggs, and oils while severely limiting carbohydrate-rich foods such as bread, pasta, fruit, and sugar. The Atkins diet has been popular since its inception, and many people have used it successfully to lose weight and maintain a healthy weight.

Atkins and other LCHF diets are based on the premise that carbohydrate consumption increases levels of insulin in the blood. Insulin is a hormone that helps the body covert food into energy in the form of glucose (sugar) and that stores excess carbohydrates as fat. High insulin levels have been linked to medical conditions such as type 2 diabetes, cardiovascular disease, and obesity. Eating fat does not raise insulin nearly as much as eating carbohydrates, especially refined carbohydrates and sugar. By reducing insulin levels through limiting carbohydrate consumption, the body will burn fat for fuel instead of using sugars, and the person will find it easier to lose weight without hunger. Protein has a similar appetite-suppressant effect to fat.

Phases of the Atkins diet

Induction: At least two weeks

No more than 20 net carbohydrates per day (with 12–15 grams from low-carb vegetables)

Liberal amounts of protein, including meats, fish, poultry, and eggs, as well as healthy fats

Fatty condiments (mayonnaise, sour cream, olive oil, butter) are allowed in unlimited quantities

Weight loss during the induction phase may be significant

Ongoing weight loss: Begin after two weeks

Slow introduction of foods with carbohydrates that are considered nutrient dense (nuts, berries, seeds)

In week one, eat 25 grams of carbohydrates per day

In week two, 30 grams of carbohydrates are allowed

The addition of five grams per week continues until weight loss stalls, then drop back to the previous gram level

Pre-maintenance goal: Begin when within 5–10 pounds of weight-loss goal

Gradually increase carbohydrate intake by 10 grams per week until weight loss stops, then drop back to the previous carbohydrate gram level

Level weight loss to less than one pound per week

Add in some fruits, whole grains, and starchy vegetables

Lifetime maintenance: Begin one month after weight-loss goal is achieved

May be able to consume from 75 to 120 grams of carbohydrates a day, depending on age, gender, and activity level

Maintaining weight goal is more likely if carbohydrate intake remains at the level discovered in pre-maintenance

SOURCE: Atkins Diet Official Website. “Atkins 20: Phase 1: Induction.” (accessed April 3, 2018).


Robert C. Atkins, a cardiologist and internist, developed the Atkins diet in the early 1970s. The original premise for developing the diet came about because of Atkins' frustration with the increasing rates of American obesity and chronic diseases such as type 2 diabetes. The diet first came to public attention in 1972 with the publication of Dr. Atkins' Diet Revolution. It quickly became a bestseller, and it remained very popular until about 2004. Dr. Atkins personally treated a number of overweight patients who are overweight with his low-carb diet and found that it produced clear improvements for people suffering from obesity and diabetes.

Before his death in 2003, Atkins authored many books, including cookbooks and many books promoting variations on his diet. After his death, the popularity of the diet declined substantially. In 2005, Atkins' company, Atkins Nutritionals, filed for Chapter 11 bankruptcy. Until 2005, the company had concentrated on providing diet information through the sale of its books. When the company emerged from bankruptcy in 2006, it had a new business strategy that focused on providing low-carbohydrate foods (mostly shakes and bars) that conform to the Atkins diet.

In the 2010s, renewed interest in low-carbohydrate diets brought attention back to the Atkins diet. This interest was spurred by the rapidly increasing epidemics of obesity, diabetes, and hyperinsulinemia, which grew steadily starting about the time that the USDA recommended a low-fat /high-carbohydrate diet in the late 1970s. Work by researchers such as Gary Taubes, Nina Teicholz, Jason Fung, and Tim Noakes called these low-fat guidelines into question and suggested that a high-carbohydrate/high-sugar diet might instead be at the root of the obesity epidemic.

The Atkins company adjusted the diet slightly in the 2010s. In 2015, the company introduced the Atkins 40 program, which allowed 1.41 oz. (40 g) of carbohydrates per day in the induction phase, twice the amount than had been the case with an earlier version called Atkins 20. The company is working to create a diet that people can follow long-term, with emphasis on healthy fats and moderate protein along with a substantial consumption of vegetables. After losing weight, people can try adding carbs back in up to about 3.5 oz. (100 g), as long as this does not make the weight come back.


The Atkins diet has been one of the most popular diets in the United States. It started a low-carb revolution, leading to the development of low-carbohydrate choices in grocery stores and restaurants. The regimen ranges from low-carbohydrate to very-low-carbohydrate, or ketogenic (i.e., deriving 10% or fewer of calories from carbohydrates). Low-carb diets reduce insulin levels, which is necessary to persuade the body to burn fat instead of storing it. They also reduce appetite, because of the increased protein intake, making it easy for people to eat less food and to go many hours between meals without feeling hungry. The Atkins diet is known for producing rapid initial weight loss followed by steady long-term weight loss as the body burns stored fat for energy.

The Atkins diet consists of four phases that participants are expected to progress through to achieve and maintain weight loss. Throughout these phases, the dieter is encouraged to drink at least eight 8-oz. (.25-L) glasses of water daily to avoid dehydration and constipation, to take a good multivitamin supplement, and to exercise to speed weight loss.


The four-phase diet starts with a two-week induction program designed to rebalance an individual's metabolism. This is by far the most restrictive of the four phases. Unlimited amounts of fat and protein are allowed, but carbohydrate intake is restricted to no more than 1.4 oz. (40 g) per day. Foods allowed include butter, oil, mayonnaise, sour cream, guacamole, meat, poultry, fish, eggs, cheese, and cream. The Atkins theory is that high-fat foods enhance the flavor of meals, making the Atkins diet easier to maintain. The daily amount of carbohydrates allowed equals about 3 c. (.71 L) of salad vegetables, such as lettuce, cucumbers, and celery. Dieters may feel hungry for the first 48 hours as their bodies adjust to the abrupt reduction in carbohydrates. They may also experience the “low carb flu,” a feeling of general malaise, fatigue, and loss of energy. This goes away if a person remains on a low-carb diet.

Atkins Nutritionals claims that the induction phase can make people feel revitalized. Carbohydrates can cause blood sugar spikes that lead to fatigue and other symptoms, and removing carbohydrates allows for a steadier supply of fuel. The program also claims that the induction phase will help dieters see the benefits of fat burning and strengthen their immune systems. Weight loss during this phase often is often substantial and quick, which can motivate the dieter to continue.

Ongoing weight loss

The second phase of the Atkins diet moves into ongoing weight loss. It involves the slow introduction of foods containing carbohydrates that are also considered nutrient dense and allows.53-1.4 oz. (15-40 g) of carbohydrates per day. Most of the carbohydrates come from vegetables. Atkins dieters still eat a high proportion of proteins and fat, but they gradually add more carbohydrates into the diet. The purpose of the phase is to continue to burn fat while controlling appetite and cravings. This phase also introduces the dieter to a broader range of foods and helps determine the dieter's threshold level of carbohydrate consumption (the maximum amount that still promotes weight loss). It is the intention of this phase to deliberately slow weight loss.

If weight loss continues, carbohydrate intake is gradually increased each week. This process of allowing an additional.18 oz. (5 g) of carbohydrates per day continues on a weekly basis up to about 3.5 oz. (100 g), or until weight loss stalls. Then the dieter drops back to the previous gram level.

Typical tolerance levels range anywhere from 1.1–3.2 oz. (30–90 g) of carbohydrates per day. The more dieters exercise, the more carbohydrates they can consume and still lose weight. The Atkins diet recommends choosing first from vegetables that are low in carbohydrates, then from other sources that are fresh foods high in nutrients and fiber. Examples of low-carbohydrate vegetables are lettuce, raw celery, and cucumbers. Nutrient-rich carbohydrates include green beans, Brazil nuts, avocados, berries, and whole grains.


The Atkins diet considers the third phase as practice for lifetime maintenance of the individual's goal weight and healthy eating habits. When the dieter is within 5–10 lb. (2.3–4.5 kg) of the goal weight, carbohydrate intake gradually is increased by.35 oz. (10 g) per day each week until weight is gained. Then the dieter drops back to the previous carbohydrate gram level. The purpose is to level weight loss to less than 1 lb. (.45 kg) per week. The dieter should continue at this rate until the goal weight is reached and for one month past that time. The goal is to achieve a level at which weight is neither gained nor lost and to internalize habits that become part of a permanent lifestyle.

Examples of vegetables that contain about.35 oz. (10 g) of carbohydrates are.75 c. (.18 L) of carrots,.5 c. (.12 L) of acorn squash, 1 c. (.24 L) of beets, and.25 c. (.06 L) of white potatoes. Legumes and fruit are the next preferred food groups for adding.35 oz. (10 g) daily. One-half apple contains.35 oz. (10 g) of carbohydrates, as does.33 c. (.08 L) of kidney beans.

Lifetime maintenance

This final phase of the Atkins diet occurs when the dieter's goal weight is reached. Although an adult may be able to consume 3.2–4.2 oz. (90–120 g) of carbohydrates daily, depending on age, gender, and activity level, maintaining the goal weight is more likely if carbohydrate intake remains at the level discovered in pre-maintenance, generally in the range of 1.4–2.1 oz. (40–60 g) of carbohydrates per day. The key, according to Atkins, is never letting weight vary by more than 3–5 lb. (1.4–2.3 kg) before making corrections.



Atkins and his followers believe that the traditional approach to weight loss of counting calories and cutting fat does not work. They suggest that carbohydrates contribute to rising rates of obesity and obesity-related diseases. Through several updates of the Atkins diet, the same basic premise has held with minor revisions. The function of the diet is to enjoy eating while severely limiting carbohydrates. The Atkins diet makes some distinctions between trans fats and other fats. A clearer distinction is also made between carbohydrates in general and sugar in particular. The Atkins diet emphasizes that protein builds energy, repairs muscles and bones, and boosts metabolism.


The obvious benefit of the diet is initial rapid and substantial weight loss, but practitioners report metabolic changes that might be more important to health than simply losing weight; reduced insulin and blood glucose levels can significantly improve the health of people with type 2 diabetes. When carbohydrate intake is severely restricted, the body burns more stored fat. No limits are set on the amount of calories or quantities of foods allowed while on the diet, so there is little hunger between meals. According to Atkins, the diet can alleviate symptoms of conditions such as fatigue, irritability, headaches, depression, and some types of joint and muscle pain.

A number of medical professionals including Dr. Jason Fung and Dr. Tim Noakes have reported tremendous success at using HFLC diets to treat patients suffering from high insulin levels, high blood sugar, high blood pressure, obesity, diabetes, and related problems. Research also suggests that a high-fat, low-carbohydrate diet such as the Atkins diet may help certain individuals with epilepsy avoid seizures. Studies have reported enhanced performance in endurance athletes. People who adopt diets like Atkins often report other benefits including improved acne, decreased sugar cravings, more energy, and clearer thinking.


Atkins is a business, designed in part to sell products. The Atkins plan produces and promotes many food products associated with its diet plan. Although the plan argues against processed foods and snacking, the company heavily promotes the use of its nutritional products to support weight loss or maintenance.

There is some concern that adherence to the Atkins diet can result in vitamin and mineral deficiencies. In his books, Atkins recommended a wide range of nutritional supplements, including a multivitamin, chromium picolinate, pantetheine, selenium, and biotin.

The average carbohydrate intake recommended by the Atkins diet is well below the average level generally recommended by other experts and federal dietary guidelines, so some experts have claimed that the diet is not healthy and does not give the body adequate fuel. Many people who adopt Atkins or other low-carb diets are convinced that it is not in fact necessary to eat these levels of carbohydrates, and that high-carbohydrate diets are a major cause of the current obesity epidemic.

Reducing carbohydrates can have the effect of reducing dietary fiber intake. The health benefits of fiber are well-established. A person following the Atkins diet should eat sufficient vegetables and fruits to get adequate fiber, and supplement if necessary.


According to Atkins, this diet causes no adverse side effects, at least not in the long term. As is the case with all low-carb diets, the initial days of low-carb eating can cause what is known as induction flu, two or three days of headache, dizziness, fatigue, and irritability. People may also experience muscle cramps or bad breath. Constipation is also a risk due to the limited intake of fruits and vegetables, which contain dietary fiber.

People with diabetes who are taking insulin should work with their doctors to balance dosage if they change the carbohydrate composition of their diets.

Some experts have expressed concerns about the effect of a high protein diet on the kidneys, but this does not appear to be an issue for most people. A 2015 study concluded that a high-protein diet is not dangerous for most healthy people and does not produce the loss of bone mass or kidney damage that has often been posited. The concern that a high-protein diet can cause kidney damage seems to be an issue only for those with existing kidney disease. In healthy people, excess protein is broken down into amino acids and glucose. Very high protein intakes over a prolonged period may cause nausea and dehydration. Drinking more water can counter the dehydration problem.

Of greater concern for people trying to eat low-carb is that excess protein can be converted into glucose, which eliminates the benefit of reducing dietary carbohydrates. A high-protein intake causes increased calcium excretion in urine, and low calcium can lead to decreased bone health and risk of fractures. Recent studies have found, however, that although more calcium is lost, high protein intake may increase calcium absorption, helping to counteract the effects. In addition, although studies comparing low-fat diets with low-carb diets have not found differences in kidney function in patients who are obese, physicians have warned that high-protein diets may cause permanent loss of kidney function in anyone with kidney dysfunction. These risks can be avoided by limiting protein to 15% of total calories, or about.04 oz. (1 g) of protein per 2.2 lb. (1 kg) of body weight. In any case, the Atkins diet is not necessarily a high-protein diet. A ketogenic diet is usually high in fat but only moderate in protein, or 15% of total calories.

Research and general acceptance

A B-complex vitamin, found naturally in yeast, liver, and egg yolks.
A substance that removes water from the body by increasing urine production.
Ions in the body that participate in metabolic reactions. The major human electrolytes are sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl-), phosphate (HPO42-), bicarbonate (HCO3-), and sulfate (SO42-).
An elastic protein found in wheat and some other grains that gives cohesiveness to bread dough.
Ketogenic diet—
A diet with high levels of fat (around 80% of calories) and very low carbohydrates (less than 5% of calories), with the rest of calories from protein. Ketogenic diets are widely used to treat epilepsy and by individuals who find them an effective way of maintaining a healthy weight.
A metabolic state in which some of the body's energy comes from ketone bodies that result from metabolizing fat stores; ketosis is not an abnormal or unhealthy state.
An imbalance in the makeup of body fluids caused by the increased production of ketone bodies. Ketones are caused by fat breakdown.
Low-carbohydrate/high-fat (LCHF)—
A diet with high levels of fat (around 80% of calories) and very low carbohydrates (less than 5% of calories), with the rest of calories from protein.
LDL cholesterol—
Low-density lipoprotein containing a high proportion of cholesterol that is associated with the development of heart disease.

The results of scientific studies on low-carb diets in the 2000s often seemed to be contradictory. In general, research supported the idea that although short-term weight loss is often successfully achieved using the Atkins diet, long-term health may be put at risk.

More recently, however, research on low-carb high-fat diets has been positive, especially in light of the looming diabetes crisis. Researchers in India in 2017 suggested that ketogenic diets improved diabetic blood sugar, led to significant weight loss, and might be an apt dietary therapy for diabesity. A study published in JAMA in 2010 found that a low-carb, ketogenic diet was as effective at weight loss as a low-fat diet combined with the weight loss drug Orlistat, and more effective at lowering blood pressure. A 2012 study found that a ketogenic diet was more effective than a low-calorie diet at improving blood glucose levels in patients who have diabetes and obesity. In 2017, researchers at University of California found that a high-fat diet increased longevity and improved physical strength in mice.

Consumers who adopt Atkins or other low-carb diets tend to be enthusiastic about the benefits. The Internet is full of anecdotal evidence in the form of testimonials and personal stories describing easy, rapid weight loss and normalization of blood sugars.

See also Biotin ; Calcium ; Calorie restriction ; Calories ; Carbohydrate addict's diet ; Carbohydrates ; Chromium ; Constipation ; Dehydration ; Dietary guidelines ; Fad diets ; High-protein diet ; Ketogenic diets ; Metabolism ; Obesity .



Atkins, Robert C. Dr. Atkins' New Diet Revolution. New York: M. Evans and Co., 2002.

Davis, William. Undoctored: Why Health Care Has Failed You and How You Can Become Smarter than Your Doctor. Emmaus, PA: Rodale, 2017.

Fung, Jason, and Timothy Noakes. The Obesity Code: Unlocking the Secrets of Weight Loss. Greystone Books: Vancouver, Canada, 2016.

Heimowitz, Colette. Atkins: Eat Right, Not Less: Your Guidebook for Living a Low-Carb and Low-Sugar Lifestyle. New York: Touchstone, 2017.

Mercola, Joseph. Fat for Fuel: A Revolutionary Diet to Combat Cancer, Boost Brain Power, and Increase Your Energy. Carlsbad, CA: Hay House, 2017.

Noakes, Tim, and Marika Sboros. Lore of Nutrition: Challenging Conventional Dietary Beliefs. New York: Penguin, 2017.

Taubes, Gary. The Case against Sugar. New York: Random House, 2016.

Teicholz, Nina. The Big Fat Surprise: Why Butter, Meat, and Cheese Belong in a Healthy Diet. New York: Simon and Schuster, 2014.


Abbasi, Jennifer. “Interest in the Ketogenic Diet Grows for Weight Loss and Type 2 Diabetes.” JAMA 319, no. 3 (January 16, 2018):215–7. (accessed January 20, 2018).

Cuenca-Sόnchez, Marta, Diana Navas-Carrillo, and Esteban Orenes-Piñero. “Controversies Surrounding HighProtein Diet.” Advanced Nutrition 6, no. 3 (May 2015): 260–6.

Gupta, Lovely, Deepak Khandelwal, Sanjay Kalra, et al. “Ketogenic Diet in Endocrine Disorders: Current Perspectives.” Journal of Postgraduate Medicine. 63, no. 4 (October–December 2017): 242–51.

Hallberg, Sarah J., Amy L. McKenzie, Paul T. Williams, et al. “Effectiveness and Safety of a Novel Care Model for the Management of Type 2 Diabetes at 1 Year: An Open-Label, Non-Randomized, Controlled Study.” Diabetes Therapy 9, no. 2 (April 2018): 583–612.

Hamblin, James. “Getting Back with Carbs.” The Atlantic. (January 9, 2015) (accessed April 3, 2018)

Hu, Tian, Katherine T. Mills, Lu Yao, et al. “Effects of low-carbohydrate Versus Low-Fat Diets on Metabolic Risk Factors.” American Journal of Epidemiology 176, supp. 7 (October 1, 2012): S44–54.

Jenkins, David J. A., Julia M. W. Wong, Cyril W. C. Kendall. “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 4, no. 2 (February 5, 2014): e003505.

Knight, Christine. “Most People Are Simply Not Designed to Eat Pasta: Evolution Explanations for Obesity in the Low-Carbohydrate Diet Movement.” Public Understanding of Science 20, no. 5 (September 2011): 706–19.

Naude, Celeste E., Anel Schoonees, Marjanne Senekal, et al. “Low Carbohydrate Versus Isoenergetic Balanced Diets for Reducing Weight and Cardiovascular Risk: A Systematic Review and Meta-Analysis.” PLoS One 9, no. 7 (July 9, 2014): e100652.

Neal, E. G., and J. H. Cross. “Efficacy of Dietary Treatment for Epilepsy.” Journal of Human Nutrition and Diet 23, no. 2 (April 2010): 113–9.

Roberts, Megan, M. A. Wallace, A. A. Tomilov, et al. “A Ketogenic Diet Extends Longevity and Healthspan in Adult Mice.” Cell Metabolism 26, no. 3 (September 2017): 539.

Zinn, Caryn, Amy Rush, and Rebecca Johnson. “Assessing the Nutrient Intake of a Low-Carbohydrate, High-Fat (LCHF) Diet.” BMJ Open (February 8, 2018). (accessed April 3, 2018).


Atkins. “How Does a Low Carb Diet Work?” . (accessed April 13, 2018).

Eenfeldt, Andreas. “A Low-Carb Diet for Beginners.” Diet Doctor. (accessed April 3, 2018).

Virta. “Type 2 Diabetes Can Be Reversed.” Virta Health, Inc. (accessed April 3, 2018).


Academy of Nutrition and Dietetics, 120 S. Riverside Plaza, Ste. 2190, Chicago, IL, 60606-6995, (312) 899-0040, (800) 877-1600, .

Center for Food Safety and Applied Nutrition, Food and Drug Administration, 5001 Campus Dr., HFS-009, College Park, MD, 20740-3835, (888) 723-3366, .

Teresa Odle
Revised by Amy Hackney Blackwell, PhD

  This information is not a tool for self-diagnosis or a substitute for professional care.