You say "Potato"

Chris Voigt, executive director of the Washington State Potato Commission, has just wrapped up his experiment of eating only potatoes for the last 60 days. Despite being hilarious and a clear PR stint for his organization -- the event is also a case study in the odd psychology behind single-food diet obsessions.

Whether its grapefruits or sardine and avocado sandwiches -- eating the same thing day after day establishes a rigorous pattern that inevitably deprives the body of some vitamins and calories and does occasionally result in weight-loss. Over short time frames, dieters see beneficial results often because of the cognitive impact of eating a certain food.

Cognitive psychology is based on the concept that the way you think affects how you feel and what you do. Cognitive therapy, then, helps you identify your self-defeating thinking and helps you respond to it so you can feel better and behave in helpful ways. However, long-term one-food diets are impractical and dangerous. While folks may get a good short term confidence boost from one-food wonders, the crash after the fact may leave you more despondent than before. Best to think positive about a more realistic diet and exercise regime. But cognitive theory to work on a plan that has more potential to remain sustainable.