Why the Atkins Diet Still Doesn’t Work

Dr. Sears' Blog: Why the Atkins Diet Doesn’t Work and Never Will

The goal of any diet is to help you lose excess weight and keep it off. The first part is relatively easy to achieve; the second part is incredibly difficult to maintain. Any diet that restricts calories will do the first part, but invariably the lost weight returns. This is definitely the situation for the Atkins diet. I knew Bob Atkins well, and the only answer he had as to why people regain weight on his diet was that they are addicted to carbohydrates. Frankly, I never bought into that explanation from Bob any more than I believed the reasoning of the advocates for low-fat diets saying the failure to maintain weight loss is because people are addicted to fat. To paraphrase former President Clinton, “It’s the hormones, stupid.”

In most cases what really causes weight regain is cellular inflammation induced by hormonal imbalance. This is why any diet that uses the word “low” or “high” to describe itself will induce hormonal imbalance, and therefore ultimately fail. Low-fat diets are generally high-carbohydrate diets. High levels of carbohydrates will increase the production of insulin, which is the hormone that makes you fat and keeps you fat. This increase in insulin will generate increased cellular inflammation that increases the likelihood for weight regain (1). On the other hand, the Atkins diet is a low-carbohydrate diet that is also a high-fat diet. If those fats on the Atkins diet are rich in saturated and omega-6 fats (which they usually are), then their presence will also increase cellular inflammation (1). This increase in cellular inflammation (by either type of diet) disrupts hormonal signaling patterns (especially for insulin signaling) that generate increased insulin resistance. This was shown in one of my earlier research articles that demonstrated that under carefully controlled clinical conditions, following the Atkins diet shows significant increases in cellular inflammation compared to those subjects following the Zone Diet (2). In addition, there was decreased endurance capacity of the subjects on the Atkins diet compared to those on the Zone Diet (3).

The differences are probably due to the fact that the  anti inflammatory diet is a diet that is moderate in protein, carbohydrate and fat. It’s this type of dietary moderation of macronutrients that generates hormonal balance.Now new data from Yale Medical School indicates that a ketogenic (i.e. Atkins) diet may even have worse health implications than simply weight regain (4). In this study, it was demonstrated that although indicators of insulin resistance in the blood may be decreased on a ketogenic diet, insulin resistance in the liver was dramatically increased. Since the liver is the central processing organ for controlling metabolism, this would suggest that long-term use of the Atkins diet would cause metabolic problems leading to accumulation of excess fat. Adding even more fuel to this hormonal fire is another study that demonstrated that a ketogenic diet leads to increased production of cortisol (another hormone that makes you fat and keeps you fat) in the fat cells (5). Any increase in cortisol increases insulin resistance in that particular organ.

So it appears that ketogenic diets (like the Atkins diet) may initially reduce insulin levels in the blood, but increase insulin resistance in organs, such as the liver and the adipose tissue. The bottom line: Any initial weight loss with the Atkins diet is a false hope since it causes insulin resistance in various organs that ultimately cause the regain of any lost weight as excess fat. That’s a very bad prescription.


  1. Sears B. “Toxic Fat.” Thomas Nelson. Nashville, TN (2008).
  2. Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, and Sears B. “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 83: 1055-1061 (2006).
  3. White AM, Johnston CS, Swan PD, Tjonn SL, and Sears B. “Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: a pilot study.” J Am Diet Assoc 107: 1792-1796 (2007).
  4. Jornayvaz FR, Jurczak MJ, Lee HY, Birkenfeld AL, Frederick DW, Zhang D, Zhang XM, Samuel VT, and Shulman GI. “A high-fat, ketogenic diet causes hepatic insulin resistance in mice, despite increasing energy expenditure and preventing weight gain.” Am J Physiol Endocrinol Metab 299: E808-815 (2010).
  5. Stimson RH, Johnstone AM, Homer NZ, Wake DJ, Morton NM, Andrew R, Lobley GE, and Walker BR. “Dietary macronutrient content alters cortisol metabolism independently of body weight changes in obese men.” J Clin Endocrinol Metab 92: 4480-4484 (2007).

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About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 45 years to the study of lipids. He has published 40 scientific articles and holds 14 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 14 books, including the New York Times #1 best-seller, The Zone, which have sold more than 6 million copies in the U.S. and have been translated into 22 different languages.


  1. Daniel K.

    The article cited as evidence that a high fat diet causes organ insulin resistance does not mention what types of foods were used as fats. Does anyone know? I think that is an important variable. The paper says only that they were fed 95% calories from fat.

    • Daniel K.

      I see now that my comment about reference also applies to reference 5: The papers do not detail the actual foods/fats used. Seems like a glaring hole for an article concerning nutrition…

    • Barry Sears

      In animal studies with mice, a high-fat diet is usually 60% fat coming from lard. That would be a rich source of palmitic compared to the usual rat chow diet of 10% fat.

      A true ketogenic diet for treating epilespy is about 75% fat (much coming from cream) with remainder being fat and carbohydrate. This diet highly unpalatable and rarely maintained for any period of time in spite of its benefits. The standard Atkins diet is 60% fat (also high in palmitic acid), 30% protein, and 10% carbohydrates.


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