Extra fat means more happiness, better sex - One of the world's most revered scientists has developed a theory that fat people are happier than thin ones. James Watson, the Nobel prize-winning geneticist who was jointly responsible for discovering the structure of DNA, believes that plumper women are also likely to enjoy a better sex life than their thin counterparts. Watson, who directed the successful human genome project, has moved into the controversial science of body image. He recently told an audience at University College London that his research suggested extra pounds had the biological effect of making a woman well-rounded in character and better in bed.