A study in 1996 showed that chocolate caused the release of endorphins in the brains of American women, making them feel happy.
Chocolate does contain a number of compounds associated with mood-lifting chemicals in the brain. Often mentioned is phenylethylamine, a natural antidepressant and one of the chemicals your brain produces as you fall in love. Tryptophan, an amino acid present in small quantities in chocolate, is linked to the production of serotonin, a neurotransmitter that produces feelings of happiness. A handful of other substances also add to chocolate’s purported effects – for example theobromine can increase heart rate, and caffeine is well known as a ‘wake-up’ drug.
But most of these compounds are present only in small quantities in chocolate, and now some scientists say that they are probably almost entirely digested before they reach the brain. It may instead be the experience of eating chocolate, and satisfying a food craving, that releases endorphins and ‘happy feelings’ more than the content of the chocolate itself.