If you ever find yourself digging through the fridge looking for food when you’re not really hungry, it could be more than a lack of willpower that’s to blame. Scientists believe the phenomenon could be the result of a hormone deficiency in the brain. 
A report published this week in the journal Cell Reports suggests that a lack of the hormone glucagon-like peptide-1, or GLP-1, in the brain could be a cause of overeating. GLP-1 is secreted from cells in both the small intestine and the brain to let our brains know when we’ve had enough to eat. 
Researchers from Rutgers University looked at how levels of GLP-1 affected laboratory mice. When the hormone was introduced in the mice, the rodents overate or consumed more high-fat food. When scientists enhanced the signal, they were able to block the mice’s cravings for fatty foods.
Until now, little was known about how our nervous system uses hormones to regulate how much we eat and when we stop. Zhiping Pang, an author of the study and a professor at Rutgers, said further research using human stem cells from people with eating disorders should provide more insight into hedonic hunger, which makes us eat for pleasure rather than for energy.
This area of the brain also controls other addictive behaviors such as drug, alcohol and nicotine addiction. According to Pang, understanding more about GLP-1 could have broader inferences for how the brain’s chemistry impacts the other motivational behaviors. 
The researchers noted in the report that social and cultural pressures, as well as psychological issues like depression, also contribute to overeating.
Earlier this month, a study published in the Proceedings of the National Academy of Sciences detailed how Harvard University geneticists had discovered that the cave-dwelling fish Astyanax mexicanus, which are known to regularly overeat, have the same genetic mutation found in a small population of severely obese people. Researchers have already identified variations to the MC4R gene found in some overweight individuals who eat compulsively. 
One study found that mutations in the MC4R gene exist in approximately one to 2.5 percent of people with a body mass index (BMI) of greater than 30. Adults with a BMI of between 25 and 29.9 are considered overweight; adults with a BMI of 30 or greater are considered obese.