Schematic representation of the natural history of obesity. Schematic representation of the natural history of obesity. Primary (excess) weight gain occurs usually over years against the typical background of mild age-related increase in weight in the general population. Intentional weight loss frequently is at least partially successful, but in the vast majority of cases, is followed by weight regain. Weight loss and its maintenance is the therapeutic goal; prevention of primary weight gain is a societal endeavor. Robert H. Eckel et al. Dia Care 2011;34:1424-1430 ©2011 by American Diabetes Association