We all know chocolate is an aphrodisiac. It contains an endorphin called phenylethylamine, levels of which in the brain have been linked to falling in love. Chocolate has been used as a gift since the days of the Aztecs, who believed it to be a source of spiritual wisdom, energy and higher sexual prowess. It was used as a nuptial aid and served at wedding ceremonies. How could the Aztecs be wrong? They invented the stuff, after all, along with popcorn and universal education