There are two hormones that have a big impact on whether we feel hungry or full, which has implications when it comes to how much we eat and therefore whether we lose or gain fat. I’ve talked about leptin, the hormone of satiety, before, which must mean it’s ghrelin’s turn.
Ghrelin is often called the “hunger hormone” because it’s what makes you want to eat. Ghrelin also has other important roles, like influencing your blood sugar levels, gastric acid, how you sleep and even your sense of taste. It can also help protect your heart, reduce the risk of muscle atrophy and affect bone formation and metabolism (https://pubmed.ncbi.nlm.nih.gov/24100676/). That’s on top of its role in fat gain and storage.
That’s a lot for one hormone to do. No wonder scientists are so fascinated by its possibilities for treating all kinds of conditions, including obesity. However, there aren’t currently any ways for us to artificially control our ghrelin levels. It can be affected by your diet and weight, but there’s no way to just take a supplement to raise and lower it. You just have to rely on your stomach producing it when it’s needed and sending it through the blood to the brain at the right time.
As it stands, our ghrelin levels rise when it’s been a while since we’ve eaten, normally just before we have another meal. This doesn’t mean that people who are obese have higher ghrelin levels. Research suggests that they may just be more sensitive to ghrelin or have an overactive ghrelin receptor (https://pubmed.ncbi.nlm.nih.gov/27288828/).
One theory is that back in the olden days when food was scarce, ghrelin helped make sure we could eat and store fat for the hard times. People who are underweight could certainly benefit from more ghrelin. If you’re going on a diet to try to lose weight, however, too much ghrelin is not helpful. This is particularly annoying because as soon as you start reducing your food and calorie intake, ghrelin will rise. Yes, this means dieting makes you hungry, which is the opposite of what you want. No wonder it’s hard to stick to a diet!
The best thing for your ghrelin levels is eating a stable amount and maintaining a stable weight, in addition to getting enough sleep. Let’s hope scientists can find some better ways to help us regulate this important hormone.