Table of Contents
"If your fat cells are yellin'," American TV's Dr. Oz is famous for saying, "the problem is ghrelin." Ghrelin is a hormone the stomach release to send a message to your brain that you are not full yet. When your stomach releases this hormone, you feel a literal, physical pain for food, until you eat, and possibly eat some more.
Feed Me 'Til I Want No More
The reason the hormone ghrelin keeps us fat is that it acts on our brain in ways that make high-calorie foods look more attractive than low-calorie foods. Obesity researcher Tony Goldstone, MD, PhD, senior clinician scientist at MRC Clinical Sciences Centre at the Imperial College of London and Hammersmith Hospital, recruited 18 normal-weight, young, healthy adult men and women to submit to MRI brain scans after overnight fasting followed by more fasting or a 730-calorie breakfast and a shot of either ghrelin or saline solution.
Goldstone found that whether the volunteers had eaten or not, and whether they had been given an injection of ghrelin or not, foods like carrot sticks and salad didn't "light up" the anterior orbital frontal cortex, the part of the brain involved in food-seeking behavior. When the volunteers ate the breakfast and were given an injection of saline, high-calorie foods like pizza did not cause the brain to light up on MRI, either. But when the volunteers were not fed breakfast, or when they were fed the breakfast and given a shot of ghrelin, their brains lit up especially bright when they were shown photos of high-calorie foods.
Ghrelin resets the brain to direct food-seeking behaviors as if the stomach were empty, even when it's full. Ghrelin probably is responsible for binge eating and compulsive eating. And some people are genetically programmed to create a double dose of this gotta'-eat chemical.
The Gene That Keeps You From Fitting In Your Jeans
Scientists have known since 2007. that the production of ghrelin is programmed by a gene called FTO. More recently, scientists have discovered that there are two versions of the gene that they label A and T. Everyone has two FTO genes. If you inherited the AA combination, you are 70% more likely to become obese than if you inherited the TT combination. You are genetically programmed to want to keep eating after you are full, and you are genetically programmed to eat high-calorie foods.
But what can you do about that?