It’s Hard to Lose Weight, but the Mediterranean and the Atkins Diets are Best

Three weight loss diets were compared over the course of two years in a newly published clinical trial conducted in Israel. The “winners” are the Mediterranean and the Atkins diet. People on one of these two diets lost more weight than the people on the low-fat diet long recommended by the American Heart Association and many physicians.

The differences and the amounts of weight lost were not great, ranging from 6 1/2 to 11 pounds. The results, however, call into question the dire health warnings about going on the Atkins diet, which is high in fat and protein and represented in this study as the low-carbohydrate diet. Published last month in The New England Journal of Medicine, the study was partially funded by the Dr. Robert C. and Veronica Atkins Research Foundation. It was so well designed that one could reasonably come to the conclusion the trial provides yet-another example of just how hard it is to lose weight.

The Dietary Intervention Randomized Controlled Trial (DIRECT) Group was led by Iris Shai, RD, PhD, Ben-Gurion University of the Negev. The Israeli researchers have designed their trial to overcome the usual problems associated with diet studies that rely solely on the participants filling out extensive food-frequency questionnaires. (Who among us can accurately remember how many cups of broccoli were eaten in the last 12 months, much less the amount and type of fat used in the cooking?)

The best type of diet-study design would required the participants to be institutionalized for a year or two, so that the only foods available to them would be consistent with the diets under scrutiny. Such trials are too expensive, and not likely to get many willing participants.

The Israeli DIRECT study was conducted at a workplace in a country where lunch is the main meal. The 322 moderately obese, mostly male participants worked at a nuclear research center in Dimona, Israel, with a self-service cafeteria and an on-site medical clinic. The foods they were instructed to eat had been marked with stickers color-coded according to each participant’s assigned diet.

Each food item also had a label showing the number of calories and the number of grams of carbohydrates, fat, and saturated fat. Each food item was also labeled with a full circle (indicating “feel free to consume”) or a half circle (indicating “consume in moderation”). Here’s how the three diets were described in the study: “low-fat, restricted-calorie American Heart Association diet]; Mediterranean, restricted-calorie; or low-carbohydrate, non–restricted-calorie [i.e., Atkins diet].”

Food-frequency questionnaires were used in this study to validate the participants’ adherence to their assigned diets. The questionnaires had to be filled out three times during the two-year duration of the study. And lastly, the participants received telephone pep talks from dieticians six times. Even their spouses received educational support.

After all that effort, here’s what was accomplished after two years: The people on the Mediterranean diet and the people on the Atkins diet lost 9 and 11 pounds, respectively. And the people on the low-fat, restricted calories diet lost 6 1/2 pounds. The small number of women who participated in this study tended to lose more weight on the Mediterranean diet (14 pounds) than on the other diets.

Dr. Shai and colleagues concluded that the Mediterranean diet may be better for people with type 2 diabetes because it showed a more favorable effect on glucose and insulin levels, which the researchers attributed high consumption of monounsaturated fats like olive oil. The high-fat, high-protein Atkins diet had the best effect on cholesterol levels. Both diets were described as effective alternatives to the American Heart Association low-fat diet.

This study was supported by the Nuclear Research Center Negev, the Dr. Robert C. and Veronica Atkins Research Foundation, and the S. Daniel Abraham International Center for Health and Nutrition, Ben-Gurion University, Israel.

For More Information:

The DIRECT study is freely accessible at The New England Journal of Medicine’s Web site (www.nejm.org) Go to the July 17, 2008 issue to read, “Weight Loss with a Low-Carbohydrate, Mediterranean or, Low-Fat Diet.egy.

Maryann Napoli, Center for Medical Consumers ©
June 2008