May 7, 2012
Ghrelin Can Cause Some People To Reward Themselves With Even More Food
Ever notice how celebration and overeating often go hand-in hand? Americans celebrate holidays with formidable feasts and punctuate promotions and other happy news with plenty to eat; The proverbial fatted calf, if you will.
Now, research shows our minds could be hard-wired to chemically reward ourselves with delicious food, no matter how full we feel.
An Italian team of researchers conducted the very small study on what is called “hedonic hunger.” According to MSN, the study only involved 8 participants, and as such, the authors of the study acknowledge their findings are still in the preliminary stage.
The authors do, however, believe they have found a physiological link between indulging in foods well beyond what the body needs and a “reactive jump” in the levels of 2 key chemicals.
The first of these chemicals is ghrelin, a hormone produced in the stomach which regulates both motivation and reward. The second chemical, “2-AG” (2-arachidonoylglycerol) is involved in appetite.
“This is a very intriguing study,” said Joe Vinson, speaking to MSN. Vinson is a professor of chemistry at the University of Scranton in Pennsylvania.
“It involves the psychology of the brain, as well as biochemistry. And, yes, it´s entirely possible that this kind of chemical overriding might happen, in which the brain wants a particular kind of food even though the person is full.”
Vinson did not participate in the study.
To conduct the study, the researchers fed each of the eight participants their favorite foods and later, a less-than-favorite food of theirs of equal caloric and nutrient content. While the participants ate, the researchers measured their 2-AG and ghrelin levels. As they conducted the study, they found these levels were increased when the participants were engaged in hedonic eating, or eating their favorite foods, but not with the other, less-tasty options. The researchers say this increase suggests an activation of a chemical reward system, overriding the body´s signal that it´s had enough to eat and allowing the person to eat for sheer enjoyment rather than sustainment.
Lead Author of the study Palmiero Monteleone, MD, of the University of Naples SUN in Italy said of the study, “Hedonic hunger may powerfully stimulate overeating in an environment where highly palatable foods are omnipresent, and contribute to the surge in obesity.”
“Understanding the physiological mechanisms underlying this eating behavior may shed some light on the obesity epidemic. Further research should confirm and extend our results to patients with obesity or with other eating disorders in order to better understand the phenomenon of hedonic eating.”
According to Dr. Monteleone, the notion of “eating for fun” is relatively new. In the beginning, humans ate only to sustain themselves and prepare for long, lean seasons. Now, it appears we may be rewarding ourselves with food and eating for fun rather than survival.
The study´s results can soon be found in The Endocrine Society´s Journal of Clinical Endocrinology & Metabolism (JCEM).