Something more about obesity

The current opinion in medicine is that diet is definitely not entirely about willpower. It's controlled mostly by the brain, which gets signals and sends signals to other organs and systems implicated in metabolism. We came to think of dieting as a matter of willpower because for the past 500 years or so of Western medicine we didn't know just how many hormones, enzymes, and neurons are truly implicated in metabolism. But now we are beginning to get our heads around substances and structures within the body that have never been appreciated before.

Even if you crave food because of a nutritional deficiency, ingesting more calories than you expend or metabolize will cause weight gain. We can make a long list of the factors that can contribute to people eating more than they need or exercising less than they ought to (telly, the Internet, junk food, unsafe neighborhoods, lack of pavements in cities, dangerous weather conditions, chronic dehydration, video games, depression, inadequate local sports facilities, driving a car for work, soda consumption, gigantic food portions at restaurants, working at a desk, eating fast food, not having time to cook, not having time to exercise, a sore toe...). And there are some genetic disorders for which obesity is a symptom. But most people who are not candidates to be case studies in textbooks could theoretically lose weight by eating less and moving more. It's calories, calories, calories, all the way down. If one weighs 20 stone, it can be hard to move so exercise may be a toughie at that point, but after bariatric surgery weight loss can be maintained through diet and exercise. The dirty secret of the field of nutrition, is, however, that "energy balance" is a buzzphrase with practically no data behind it. The only way to know if you are eating the right amount of food and doing the right amount of activity is if you are in good shape and your blood test results and vital signs are all right. There are no hard and fast rules, the "food pyramid" is based on some of the worst science around, and genetics are largely responsible for dictating metabolism. We control what we decide to put in our mouths, ultimately, but the signals that ask us to pick up chocolate, coffee, dirt, pickles, ice cream, or a hamburger are very real.

The most promising new pharmacological agents for obesity do not act on the digestive system to interfere with fat storage the way that drugs like Xenical (orlistat) or Meridia (sibutramine) do. They act on the brain and the endocrine system instead. Sanofi-Aventis's pill Acomplia (rimonabant) has been through a number of clinical trials and would be the first drug in a new class called endocannabinoid receptor blockers if it is approved. The endocannabinoid system is indeed involved in the enjoyment of cannabis, but what's really interesting is that in some people, eating can excite the same region of the brain, creating a veritable addiction to the pleasure that one may experience from eating. Block the endocannabinoid receptor and eating isn't as much fun anymore so you don't want to eat; you eat only when the tummy rumbles, etc., and can lose weight. (Side note: at every talk that someone from my company has attended about rimonabant, someone who thinks he's very clever has asked a silly question like, "Did you get read more