During the last two decades, obesity rates in the United States have escalated dramatically, and intense media coverage of obesity issues has fueled consumer interest in low-carbohydrate diets designed to promote rapid weight loss. The food industry has fostered the assumption that a drop in carbohydrate consumption will translate into a drop in weight. Studies of low-carbohydrate dieters, however, have indicated that weight loss is due primarily to calorie reduction rather than carbohydrate restriction. When lowfat foods were heavily promoted, dieters assumed consumption of reduced-fat or fat-free foods would result in weight loss, unaware that calorie consumption could increase even if fat intake was reduced. This pattern is likely to be repeated if escalating consumption of low-carbohydrate foods translates into increased calorie intake. Once polarized, low-fat and low-carbohydrate advocates, as well as health professionals, have moved toward agreement on a number of critical points designed to promote weight loss as well as to prevent chronic disease. These groups recommend a diet rich in fruits, vegetables, whole grains, low-fat dary products, lean meats, poultry, and fish. Despite this congruence, the weight loss industry aggressively continues to market new diets, products, and services. Ironically, as the diet business becomes more profitable, obesity rates continue to climb in the United States.