Author: Troy Theodosiou
Hunger is your body’s natural cue that it needs more food…
When you’re hungry, your stomach may “growl” and feel empty, or you may get a headache, feel irritable, or be unable to concentrate.
Most people can go several hours between meals before feeling hungry again, though this isn’t the case for everyone.
There are several possible explanations for this, including a diet that lacks protein, fat, or fiber, as well as excessive stress or dehydration.
Some hunger triggers do start in the stomach. Nerves react to a full stomach, and can signal the brain to slow or stop eating but of the process we think of as hunger and fullness comes from a tiny region at the center of the brain known as the hypothalamus. This part of the brain receives chemical signals for fullness and hunger, and sends chemical responses to regulate those feelings.
Hunger can be triggered by many things. It may be a billboard featuring steaming croissants that makes your mouth water. It may be the time of day—many people get hungry around noon if that’s when they take their lunch. It may also be a matter of habit; if you eat in front of the TV frequently, turning on the tube could trigger hunger for you. Or your body may simply need calories.
When stress first hits, it shuts down appetite as your hypothalamus preserves your resources for “fight or flight.” But ongoing stress can lead to binge eating. That’s when cortisol comes into the picture. Cortisol is a hormone that increases hunger, and it rises with chronic stress.
The water you consume doesn’t just come from the faucet. Believe it or not, a slice of brown bread is almost 40% water. An apple is nearly 70% water. And roast turkey is made of about 65% water. It’s no wonder, then, that when you think you’re hungry, you may actually be thirsty.
Most food gets turned into glucose, a sugar that can be converted into fat for use later. Insulin plays a big part in this. With some foods, your body has to work hard to get the sugar it needs. If you eat a carrot, it takes your body time to break the sugar down into a usable form, and your insulin responds relatively slowly. But if you feed yourself a high-sugar meal without much fiber, your insulin levels spike. The result is that you feel satisfied quickly at first. But sugar sends such a powerful signal to increase insulin that you’re likely to end up with more insulin than you need. And that’s why you tend to get hungry much sooner after a high-sugar meal.
At the start of this article, you learned that the hypothalamus controls a lot of our hunger signals. It does that primarily through two important hormones: leptin, which makes you hungry in low levels, and ghrelin, which makes you hungry in high levels.
One study found that leptin drops and ghrelin rises in your body if you consistently get five hours of sleep a night or less. But further studies have found similar results after just two nights spent sleeping four hours or less. This can raise ghrelin by 28% and lower leptin by 18%. And you won’t wake up hungry for a nutritional meal, either. The research shows that people with poor sleep habits become hungrier for high-carb foods loaded with calories, as well as high-fat foods. The solution is obvious—get enough sleep to avoid hunger.
It may sound strange, but sometimes it’s what you’re not eating that makes you overeat. Protein seems to be more satisfying and leaves us feeling fuller longer than other nutrients. A study performed on men of varying ages looked into this. The subjects were fed meals with plenty of protein, but the protein content decreased as the study went on. Researchers found that as protein decreased, the men became hungrier sooner after eating. That was true whether these men were younger or older.