The book offers science-based explanations — and solutions — to the two biggest problems dieters face: hitting a weight-loss plateau and regaining lost weight. Losing just 10 percent of your original body weight, followed by a six-month period of holding steady at your new weight, can help reset your set point, or typical body weight. The advice draws from experts and the 30- year career of co-author Dr. Blackburn, associate director of the division of nutrition, Harvard Medical School. The result is a lifestyle plan that extends beyond recommendations about eating and exercising.