Today's high prevalence of obesity, combined with less than satisfactory results using traditional weight-control methods, has helped foster the popularity of fad diets. Popular fad diets currently range from very low carbohydrate to very low fat, and from well-circumscribed eating patterns to grazing. This paper reviews the spectrum of fad diets in terms of rationale, claims, efficacy, and risks. Menus based on author's recommendations were compiled and assessed for macronutrients. To date, researchers have failed to reach a consensus on the potential benefits of these diets for weight loss, for preserving lean body mass during weight loss, for improving compliance with a hypocaloric diet, for preventing or treating disease, or for sustaining long-term maintenance of lost weight.