For almost a hundred years, dietitians and nutritionists have advised Americans about how to manage their weights. In a culture where being the ideal weight is interpreted as visible evidence of personal worth, dietitians and nutritionists have been sought out to assist in weight loss for esthetic as well as health reasons. Unfortunately, permanent weight loss is extremely difficult to achieve. In spite of recommendations by these professionals for changes in eating behavior that according to the laws of thermodynamics could be expected to lead to long-term weight losses, the prevalence of obesity continues to increase. This paradoxical situation creates a dilemma about how to deal with obesity when the best approaches have not performed as expected. This dilemma affects all those who work with weight management, whether from a medical, commercial, educational, or other perspective. Dietitians and nutritionists are, however, unique in the extent to which being experts in weight management is a part of their professional identity