The Obesity Germ

Obese people have more “super-digesting” intestinal bacteria, which are extremely good at extracting calories from food, and fewer of another kind of gut microbe than non-obese folks, say two studies released today in Nature. As the A.P. reports, the researchers aren’t sure yet whether having more of the calorie-loving germ actually makes you fat, or if people who are obese just produce more of that bacteria for some reason. Still, growing evidence (registration required) of this link between microbes and body mass has scientists excited about potential new treatments for obesity.

But other recent research and media reports have focused on food cravings and compared seriously overweight people to drug addicts. A small study
released in October found that obese people have the same brain responses to food (or even the idea of food) that junkies do to drugs. Even when the “hunger center” of their brains indicated that they were physically full, obese people had their memory and reward centers activated—the same parts of the brain that “light up” for drug addicts when they get an irrepressible craving for their next fix.

Can both theories be right? Well, sure; it’s entirely possible that, say, some people do have addict-like cravings for food that lead them to overeat, become obese, and consequently grow more super-digesting bacteria. But a look at other research into food cravings makes the drug-addict comparison look a whole lot less compelling and more sensationalized: Researchers have known for a while that food cravings activate the same brain areas as drug joneses, not just in obese people but in everyone. And since 100 percent of young women and 70 percent of young men report food cravings, it’s not just the obese who are affected.

Are there any studies of these issues that you’re more inclined to believe than others? Or is viewing obesity as a disease just an invitation for Big Pharma to develop more drugs that we don’t really need?