By now it is common knowledge that being severely overweight puts people at increased risk of suffering from heart disease, stroke and diabetes and that obesity—defined as weighing at least 20 percent more than the high side of normal—is on the rise. According to one estimate, the U.S. will be home to 65 million more obese people in 2030 than it is today, leading to an additional six million or more cases of heart disease and stroke and another eight million cases of type 2 diabetes. Many clinicians have already begun seeing families in which the grandparents are healthier and living longer than their children and grandchildren.