Headline-Making Diet Comparison Delivers a Mixed Message

What's the real takeaway of the recent, much-publicized study in Israel pitting the controversial Atkins diet against low-fat and Mediterranean-style plans? That depends on your point of view:

* The Atkins Research Foundation, which partly financed the study but had no role in the trial, called it "a vindication" because the Atkins group lost the most weight over two years — an average 12 pounds, compared to 10 on the Mediterranean diet and 7.3 on the low-fat diet.
* The Mediterranean Foods Alliance pointed out that the 45 women among the 322 dieters actually lost more weight on the Mediterranean diet — 14 pounds versus 5 on Atkins and less than a pound on the low-fat diet. Moreover, an Alliance statement argued, "The 'Atkins-style' low-carb diet used in the study might better be described as 'Atkins goes Med.'"
* Because all three groups showed improvements in the ratio of good (HDL) to bad (LDL) cholesterol and other health indicators, lead author Iris Shai, PhD, RD, of Ben Gurion University of the Negev emphasized, "This suggests that healthy diet has beneficial effects beyond weight loss."
* In a Reuters interview, Shai added another takeaway: "The good news is, we have alternatives." Senior author Meir Stampfer, MD, of Brigham and Women's Hospital in Boston elaborated: "The findings suggest that because Mediterranean and low-carbohydrate diets are effective alternatives to low-fat diets, individual preferences could be taken into consideration when tailoring dietary interventions for weight loss."

The study garnered headlines — and so many opinions — in part because of its unusual design: a two-year trial conducted at a remote nuclear research center in Dimona, Israel. Because of the setting, where most participants ate lunch in a cafeteria with color-coded servings to help stick to each plan, and avoidance of "extreme diet protocols," 85% stuck with their assigned diet. The lowfat and Mediterranean diets did have calorie restrictions — 1,800 calories daily for men, 1,500 for women.

Besides restricting processed carbs, Atkins dieters were counseled to choose vegetarian sources of fat and protein. "But the main sources of protein were animal origin," Dr. Stampfer notes.

Average starting weight was about 200 pounds. All three groups lost the most weight in the first five months, then regained some but not all of the lost pounds.

Published in the New England Journal of Medicine, the findings in part echo another diet "face-off" in 2007, where the Atkins plan also prevailed (see the June 2007 Healthletter). The real lesson for weight loss may be similar: The low-carb Atkins diet seems to work because it's simple. Susan B. Roberts, PhD, director of the Energy Metabolism Laboratory at Tufts' Jean Mayer USDA Human Nutrition Research Center on Aging and author of the forthcoming The Instinct Diet, says losing weight is easier for some people when they cut out whole classes of foods, like processed carbohydrates.

"Other people prefer to keep a few treats and watch what they eat," Roberts adds. "The good thing is that there are several ways to eat that work. However, simpler is definitely good. When you have simple rules about what you can and can't eat, it's simpler to stick to those rules."