Sex, Drugs and Chocolate: The Science of Pleasure. Paul Martin

species, are predisposed to like foods that are rich in sugar and fat, because these are the foods that deliver the most calories. A liking for sweet, fatty foods is biologically normal, even though it has become a serious liability in our modern environment, where we are surrounded by unlimited quantities of the stuff. The particular sweet, fatty food that some individuals latch on to is milk chocolate. They learn to associate its taste and appearance with large, comforting doses of sugar and fat. Laboratory experiments have found that when self-proclaimed chocoholics have chocolate dangled in front of them, they become more physiologically aroused than other people, as judged by their increased heart rate and salivation. However, their response signifies only their anticipation of something sweet and pleasant, not a full-blown addiction to chocolate. We will see in chapter 12 that bingeing on sugar can, under certain circumstances, create an addiction to sugar. It is quite possible therefore that some extreme cases of chocoholism may be a form of sugar addiction.

      The high sugar content of milk chocolate helps to make it one of the ultimate comfort foods. We instinctively turn to sugar when we are feeling low. Experiments have found that humans and rats become more attracted to sweet things when they are in a low mood. For instance, people work harder to obtain chocolate when they have been put in a sombre mood by depressing music; similarly, rats will work harder to obtain sugar pellets when they are depressed as a result of chronic stress. For much the same reason, some people turn to chocolate when they are feeling down.