Is There Something Special about Low-Carbohydrate Diets?

Obesity is increasing rapidly and has been called an epidemic by the World Health Organization and the National Heart, Lung, and Blood Institute (1, 2). Controlling this epidemic will require an integrated strategy, including education, regulation by appropriate state and federal agencies, and modifications in food supply (3, 4). Regardless of the effectiveness of preventive strategies, some individuals will develop an unhealthy weight, reflected in a high body mass index (BMI), and will need treatment. Dietary strategies, exercise, and behavioral therapy are the cornerstones of current treatment. In this issue, Boden and colleagues (5) extend the list of studies dealing with specific popular diets—in this case, the low-carbohydrate diet. It reopens the question: Is there something special about low-carbohydrate diets?

Boden and colleagues deserve credit for a nicely done, short-term metabolic ward study. In their study, 10 obese patients with type 2 diabetes were admitted to a clinical research unit where they ate their usual diet for 7 days, followed by a low-carbohydrate diet for 14 days (20 g of carbohydrates per day and unlimited protein and fat). With this degree of carbohydrate restriction, calorie intake decreased by one third (3111 kcal/d to 2164 kcal/d), and the participants became more insulin-sensitive. What can this study teach us?

First, the study shows the importance of scholarly evaluation of popular diets, which ideally should take place before they appear in a consumer-oriented book. Popular diet books date back at least to the …