Diets work, but what good are they if the weight returns? Statistics show that 80 to 90 percent of dieters regain every lost pound. This fact represents the largest and least addressed problem in obesity management. The recidivism of dieters fuels a $30 billion weight-loss industry, an industry that would shrink like Al Roker’s waistline if the newly-thin could only make weight loss stick. But here is the problem: The skills needed to maintain a new, smaller body size are not obvious or intuitive; they must be taught. Inexplicably, books that deal successfully with ways to prevent regain have gone unwritten. Refuse to Regain, by longtime weight-management authority Barbara Berkeley, MD, fills this void. Berkeley, former medical director for the Optifast program and founder of Weight Management Partners, is a board-certified internist. She continues to have close ties to Novartis Medical Nutrition (recently acquired by Nestlé), producer of the weight-loss supplement Optifast, which has 300 weight-loss centers nationwide.