Saturday, October 18, 2008

More Obesity Studies

I am quite interested in a lot of the studies that keep being published about obesity, genetics and so on. I read about one yesterday that looks at a genetic component that decreases the pleasure some people get from food, which may impel them to eat more to get more pleasure. Here are some quotes from one of the better articles about this, from WebMD. This discussion actually reminds me a bit of the articles about ear infections being related to obesity because they damage the taste nerve. Of course none of this absolves us of the responsibility of paying attention to what we put in our mouths, it's just adding another piece to the puzzle about why it's so hard to maintain a healthy weight, especially if you've already let yourself get overweight.

"Some people carry a variant gene that dulls dopamine responses. These people, Stice found, are more likely to be obese. And even if they are not obese, they get less pleasure from eating -- putting them at risk of overcompensating by overeating.

"People with the most blunted reward circuits are at the most risk of overeating, and the more they engage in eating, the more you see downregulation of their reward circuitry," Stice says. "They eat more to get the same reward."

"Of course it is a vicious circle," says Pothos. "A person says, 'I do not get pleasure from high-energy food, so I am eating even more but getting less pleasure, I don't know what to do. So obesity and weight gain may result from what we may call addiction to high-energy food."
"The term "addiction" isn't a metaphor. Stice and Pothos note that the same vicious circle, involving the same brain circuits and the same underlying genetic susceptibility, occurs in people addicted to drugs.

"However, both researchers are quick to point out that a dysfunctional pleasure system is only half the answer to the puzzle of obesity. Metabolic functions that control body weight also play a major role.

"We don't want to say obesity is an addictive disorder and not a metabolic disorder. We just want to say, 'Pay attention to both,'" Pothos says.

"Stice is now looking at whether obese people who switch to a healthy diet can reset their pleasure circuitry. He finds that when obese people stop eating energy-dense foods, their craving for such foods goes down, not up.

"If we can get obese people to improve the quality of their diets and stay the course for long time, eventually they do much better in craving and their pleasure circuits should go back to their old balance," he says."
One of the articles said that exercise helps in decreasing the cravings because it activates the same dopamine pathways that eating does. The other way to avoid the problem is to not start eating the junky stuff to begin with. Ha ha, too late!

A couple of other links to articles about this: Link and Link