Sleep for more (or less) than seven hours a night and you'll put on weight - Daily Mail 1st April 2008

Seven hours of sleep a night could be the recipe for staying in shape, say researchers. Too much or too little sleep piles on the pounds, and over the years can end in obesity. A study has found that those sleeping for less than seven hours a night gained four pounds in six years. Those sleeping for more gained three pounds over the same period.

Link to Article