A man takes a bite from a hot dog in Hollywood, October 3, 2007. What people eat and how fast they grow are both significant causes of cancer, but many Americans still incorrectly believe that factors such as pesticides on food are bigger causes, experts reported on Wednesday. (Lucy Nicholson/Reuters)Reuters - Keeping slim is one of the best ways of preventing cancer, as is avoiding excessive amounts of red meat and wine, a landmark study has revealed.