A hundred years ago, doctors had no cure for the clap. They insisted, instead, that people practice monogamy and continence as a cure for what ailed them, and when patients confessed to extramarital sex they got stern lectures about how it was all their own fault they were breaking out in boils. Today we are more modern, and above that sort of Victorian thinking... or are we? Actually, no, we're not. Substitute "obesity"for "the clap" and nothing has changed. The scowls are the same and so are the lectures... because doctors still hate to admit they don't know the cure.