Obesity: a "brain disease"?

Have you ever been grocery shopping when you’re hungry, and bought way more stuff than you intended? Understanding the reasons for this may give us some clues to the obesity epidemic, new research suggests.

People generally eat for two reasons: because they’re hungry (hormones in the brain tell us to eat to maintain a constant body weight), or because we’re tempted by delicious food (so-called “hedonistic consumption”). But it could be these two urges are more interconnected than we previously thought: researchers at the Montreal Neurological Institute, McGill University say they’ve discovered that ghrelin (one of the hormones that prompts us to eat when we need more calories) might also make us want to consume food for pleasure.

“Our study demonstrates that ghrelin actually activates certain regions of the brain to be more responsive to visual food cues, thereby enhancing the hedonic and incentive responses to food-related cues,” neurologist Dr. Alain Dagher, principal investigator in the study, says in a press release. “Ghrelin is a hormone that triggers hunger, and is secreted by the stomach [when it is empty].”

This supports the view, the press release notes, that “obesity must be understood as a brain disease and that hunger should also be looked at as a kind of food addiction,” as obese people might be overeating largely due to an uncontrollable hunger.

Researchers found ghrelin actually acts on the same reward and motivation areas of the brain implicated in drug addiction, which could potentially have profound implications: “If food is thought of as potentially ‘addictive,’” the press release says, “this would support action to limit or ban fast food from schools and junk food advertisements geared towards children, in the same way that results proving nicotine to be addictive spurred the current public policy towards nicotine.”