This hunger-stimulating hormone acts on receptors in the hypothalamus region of the brain, which essentially tell us that we are hungry. After we eat a meal, the hormone levels begin to dissipate.
While ghrelin may serve a biologically important role in survival, for most people in the civilized world who have no problem with ample access to foods, it can also pose a pretty big challenge. That’s because studies have shown that ghrelin doesn’t just make us want to eat, it makes highly caloric foods the most desirable to us.
Grehlin may also help explain why extreme deprivation diets are doomed for failure. By going without food for an extended period of time, or simply not getting adequate nutrition, the grehlin may strongly influence a person to crave high calorie foods.
But it doesn’t stop there.
Evidence is growing that there is an emotional component to ghrelin’s action on the brain. Multiple studies suggest it influences our food choices by acting on the brain reward systems. In other words, we are attracted to the pleasure we experience when eating our favorite dietary indulgences.
All of this makes it much clearer why we feel compelled to reach for pizza or chocolate cake, rather than a salad. It also shines a light on the emotional challenges for people trying to lose weight. For example, let’s say an obese person who is already in a fragile emotional state goes on a diet, maybe too extreme in its calorie restriction.
When the body produces grehlin in response, the person will likely gravitate towards high-calorie foods and go off their diet. Since there is an emotional reward and pleasure associated with it, the person may sink deeper into their old ways (since they feel content or “rewarded” for their actions).
Even so, none of the research comes to the conclusion that we are at the complete mercy of our hunger hormones. In fact, research has shown that people who decide to show dietary restraint have less activity in the orbital frontal cortex. In effect, our decision-making overrides the reward system.
The moral of the story? You have the power!