RESEARCH MEDICINE FAT IS ADDICTIVE Ever wondered why it’s so difficult not to empty a bag of crisps? And do you criticize yourself for eating that extra piece of luscious chocolate pie? Research now shows that you don’t need to blame yourself for your lack of self-control: Our brains are addicted to fatty foods. From an evolutionary perspective, it makes sense for us to like fatty foods. They are an essential ingredient of our nutrition and were a rare commodity for our ancestors. In the present, however, all kinds of fast foods are available to us, so there is certainly no lack of foods that contain fats. But people apparently aren’t able to keep themselves from eating fatty foods, which causes them to become overweight and unhealthy. Piomelli and colleagues wanted to understand our desire for fatty foods. In their research, reported in the July 5 edition of Proceedings of the National Academy of Sciences, they reported that when rats taste fat, it stimulates the same cellular buttons triggered by the active ingredient in marijuana. These so-called endocannabinoids, which are released in the brain and body, seem to tell the body to keep eating. The results are important for understanding binge eating and weight related problems and might lead to new ways that will help people overcome weight problems. The researchers fed rats one of four liquid diets: fat (in the form of corn oil), protein,
sugar or a nutrition shake combination of fat, protein and sugar. To ensure that the body’s digestive signals wouldn’t interfere with the experiments, a surgically implanted valve in the rats’ upper stomach drained the food once eaten. Then the team measured endocannabinoid activity in the brain and other tissues. Rats on the fat diet had a surge of endocannabinoid activity in their gut, compared with rats eating sugar or protein alone. And these rats wouldn’t stop slurping their corn oil. When given a compound that blocked the cellular buttons that the endocannabinoids typically hit, the fat-eating rats immediately stopped eating. The research suggests that when drugs are administered to humans that block these endocannabinoid-sensitive buttons, we may be better able to refrain from eating excessive amounts of fatty foods.