Atkins Put to the Test

May 7, 2007
Nutrition is complicated. It's not a bad thing to question the science underlying conventional wisdom.

A study recently published in the Journal of the American Medical Association compared three popular weight-loss diets: Atkins, Zone and Ornish. Also included was a less well-known diet referred to by the acronym LEARN, based on national dietary guidelines.

As was widely reported, the Atkins diet outperformed the other three in terms of greater weight loss while not causing adverse metabolic effects such as increased cholesterol or triglycerides.

The methodology of the study was simple. A total of 311 dieters were enrolled; all were overweight women aged 25 to 50 years. They were divided into four equal groups, about 77 women per group, each assigned to one of the diets.

Each group attended a series of eight one-hour classes in which they were instructed on their diet. It was then up to each individual dieter to either follow or not follow her diet plan. Weight loss and several other parameters were measured over the next 12 months, and the results were analyzed statistically.

At the end of 12 months, those in the Atkins group had lost an average of 10.3 lbs. each, roughly twice as much as the other groups, whose average weight loss ranged from 3.5 lbs. to 5.7 lbs. The results at six months were slightly more significant, with the Atkins group having lost about 13 lbs. each.

The Atkins group had about half as many drop-outs over the 12-month period as each other group. In all groups, the average body mass index at the end of 12 months remained higher than recommended. As critics of the study pointed out, these results are not all that dramatic. In fact, it's discouraging that greater weight loss was not measured across the board. Furthermore, this study did not measure the effects of each diet if followed strictly. A complicating factor is the unknown extent to which each participant followed her diet.

However, this study design did measure, in a reasonable way, the likely real-life effect each diet will have on an ordinary person committed to following a diet plan while being observed. Most interestingly, the Atkins diet did outperform the others while not visibly harming anyone's health.

The Atkins diet has long been vilified by traditional nutritionists and others. At least one web site,, is devoted to attacking the diet. A much-discussed cover story in the Sunday New York Times Magazine explored the merits of the Atkins diet in a favorable way ("What if It's All Been a Big Fat Lie?" July 7, 2002). The article was immediately and ferociously attacked. The Center for Science in the Public Interest (CSPI) published an entire cover story-rebuttal in its Nutrition Action Health Letter. This was not surprising as CSPI's credibility and livelihood is tied up in traditional nutritional advice.

The Physicians Committee for Responsible Medicine (PCRM) took things a step further, staging a lawsuit against Atkins Nutritionals in which a former dieter attributed symptoms of heart disease to the Atkins diet. As with CSPI, the PCRM's motives were transparent: It advocates vegetarian and vegan diets and is concerned with animal welfare.

Critics of the Atkins diet often react to the diet as if a person is intended to remain on it indefinitely. In fact, it's intended as a weight-loss program, and a sensible person will revert to a normal diet, incorporating recommended amounts of fruits and vegetables, after the pounds have been shed.

Critics have not effectively demonstrated that the Atkins diet is dangerous when followed for a limited period of time. The recent study shows that Atkins can do more good than other diets under real-life conditions and did no measurable harm over a 12-month period (in 77 individuals anyway).

All of this may not receive a tremendous amount of attention. Today, the Atkins diet seems to be viewed as a fad that has passed. More traditional thinking about weight loss (it's the calories, stupid) is back in style. But, the JAMA report should leave a few things in our minds.

Nutrition is a complicated science. It's not a bad thing to question the science underlying conventional wisdom and seek new knowledge through scientific study. And when consumer advocacy organizations tell us what's good for us, ask whether they're also influenced by what's good for them.

David Joy is a partner in the Washington, D.C., office of Keller and Heckman LLP. He specializes in food and drug law with emphasis on the domestic and international regulation of food, food additives, food labeling, antimicrobial pesticides and medical devices. He is a member of the District of Columbia Bar and holds a bachelor's degree in chemistry. For more information about Keller and Heckman, visit the firm's web site at

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