(Bloomberg Businessweek) -- Overweight and underslept, real estate executive Mel Zuckerman ignored the stern warnings from his physician: The yo-yo dieting and long hours at the office had to stop—his life depended on it. Then, suddenly, his father died, and he began to listen. It was the late 1970s, and fat camps were all the rage. But after one too many military workouts and bland, calorie-conscious meals, Zuckerman set out to dev...