Your body is designed to naturally regulate how much you eat and the energy you burn. Part of how this occurs is through the release of the hormones ghrelin and leptin.
When you eat a sugar dessert, for instance, your body increases production of leptin, which regulates your appetite and fat storage. Ghrelin, on the other hand, is known as the “hunger hormone” because people given the hormone in a study on grehlin became so ravenous, they ate markedly more than their usual food intake.
Ghrelin appears to act on your brain’s “pleasure centers,” driving you to reach for another slice of cheesecake simply because you remember how good the first one tasted and made you feel (at least in that moment).1
Between the appropriate releases of ghrelin and leptin, the idea is that when you eat, your body knows it should feel less hungry and you stop eating. There are many confounding factors that may derail this system, however.
When insulin is impaired (such as in case of insulin resistance), for instance, ghrelin levels remain elevated even after meal consumption a condition that leads to chronic hunger (mostly for unhealthy carbs), excess food intake and undesirable weight gain.
Your mind (and mood) also influence your food cravings, as do junk foods created with the intention to hook you and encourage you to eat more.
‘Hunger Neurons’: Your Body Is Hard-Wired to Have a Negative Response to Hunger
When you’re hungry, hypothalamic AGRP (agouti-related protein-expression) neurons trigger unpleasant feelings in your body. This, in turn, drives you to seek food in order to relieve these negative feelings.2 In times when food is scarce, this innate mechanism could be life-saving.
Seeking your next meal at one time required potentially putting yourself in a risky situation, so your hunger neurons’ ability to drum up negative feelings served as a poignant push to find food.3
Today however, if food is readily available you can eat to your heart’s content, and part of the motivation to do so (albeit subconsciously) is to silence your AGRP neurons and feel better.
This isn’t an entirely bad thing, and your body should be able to regulate its food intake nonetheless, except that nowadays this negative response to hunger is paired with a positive response to junk food, representing the perfect storm for junk-food addiction and weight gain.