He knew he needed to lose weight fast, but he had run out of diets - all had failed.After doing some reading on evolution (why weren't our forebears fat?), David cut sugar - specifically fructose - from his diet. He immediately started to lose weight, and kept it off. Slim, trim and fired up, David set out to look at the connection between sugar, our soaring obesity rates and some of the more worrying disease of the twenty-first century, and discovered some startling facts in the process.