I think the only real solution to obesity in rich countries can never be diets, but a simple gene manipulation which instructs the body not to save energy as fat anymore. I think exercise is just wasting valuable time, it's not like one needs to use the car every day just to keep it in good health. Of course, this gene therapy will have bad consequences also, like increase in food prices because people will eat more, but I think that will be offset by the decrease in health care costs.