Eating chocolate makes you feel good. It increases brain levels of several chemicals, including mood-altering PEA (phenylethylamine, related to amphetamine), which produces a mild, confidence-instilling buzz. Chocolate also contains tryptophan - a chemical converted to serotonin in the brain to lift mood and increase euphoria - and theobromine, a stimulant that peps you up. Chocolate is also virtually unique in that it melts in the mouth at body temperature, producing a silky, luscious sensation that adds to its appeal and, according to psychologists, is one of the main reasons why chocolate proves so addictive.