The appetite hormone ghrelin has long been known to stimulate hunger in the body, but it’s been less clear whether it may also affect the kinds of food people choose to eat. New research, however, suggests that the hormone may actually be involved in the reward pathways in the brain, and therefore be behind what leads us to choose cake over carrots.
The findings were presented at the Endocrine Society’s annual conference in San Diego last week.
It’s been known that skipping breakfast tends to lead to eating more (and possibly making bad food choices) later, which makes sense on a molecular level in light of the current study.
Tony Goldstone and his team studied 18 healthy, normal-weight adults, and had them look at pictures of food and rate how appealing they found each to be. The pictures followed one of three breakfast scenarios: in the first, the participants skipped breakfast altogether; in the second, they ate a normal meal and were later given a shot of saline solution (salt water); in the third, the participants ate breakfast but were also given a shot of the hormone ghrelin. The study was double-blind, meaning that neither the participants nor the researchers knew what kind of shot they were getting/giving.
When participants ate breakfast and then got the saline injection, they did not favor the fatty foods over the healthy foods in any noticeable way. But when they’d had breakfast and then gotten the ghrelin injection or when they’d skipped breakfast altogether, they rated the fatty foods as more appealing than the healthy choices.
In the Endocrine Society’s news release, Goldstone says that “[g]hrelin mimicked fasting in biasing food appeal toward high-calorie foods.” He adds that “[c]hanges in which foods we prefer to eat when missing meals may be explained by changes in the levels of ghrelin in our blood to help regulate our overall calorie intake.” It’s been known that skipping breakfast tends to lead to eating more (and possibly making bad food choices) later, which makes sense on a molecular level in light of the current study.
Will these findings eventually help those of us who are trying to lose weight? Goldstone says that the study “raises the possibility that drugs that block the action of ghrelin may help reduce cravings for high-calorie foods and so help people lose weight.” It may be a ways off, however, so don’t give up exercise and healthy eating in the meantime.
Tony Goldstone is a researcher at the British Medical Research Council Clinical Sciences Center at Imperial College London.