Up to 90 percent of people with type 2 diabetes are overweight. In fact, America as a nation has been packing on the pounds for the past two decades, with a whopping one-third of all adults classified as obese and skyrocketing rates of childhood obesity. Losing weight is one of the best ways to treat type 2 diabetes, but it is also possibly the most difficult. And people with type 1 diabetes have to deal with special insulin-related weight problems of their own.