Ghrelin, also known as the hunger hormone, is primarily produced within the stomach when it is empty. That said, it is also produced in other areas of the body that don’t know how much food is in the stomach, meaning that it can signal hunger even when additional energy or nutrients aren’t necessarily required. For instance, the brain, small intestine and pancreas all also produce it.
What Does the Hunger Hormone Do?
Once ghrelin is produced, it is sent through the bloodstream and into the brain. There, it acts on the hypothalamus, which is a part of the brain that produces hunger hormones, as well as those triggering sensations of thirst, mood, and other important bodily functions. While it isn’t responsible for that tummy grumbling feeling in itself, it does trigger the hypothalamus to produce that sensation, which is why it has its nickname.
As a result, the hunger hormone works as an appetite regulator. When its receptor, the secretagogue receptor – is activated, it makes us more likely to eat more food and, as a result, store more body fat.
This isn’t a problem if you’re a growing child, if you’re trying to gain weight or if you’re working to maintain your current weight. However, if you’re gaining more than you want or are attempting to lose weight, then the impact of the hunger hormone can stand in your way. People who have recently lost weight often have higher ghrelin levels, meaning that it is difficult to keep up the lost pounds due to a larger appetite than necessary.
Ghrelin and Brown Fat
Another function of the hunger hormone has to do with the brown fat on the body. Brown fat is different from the white fat associated with obesity. Brown fat actually helps to promote thermogenesis, raised metabolic rate and an improved overall ability to burn calories. Unfortunately, the ghrelin can also tell the body to slow down brown fat thermogenesis, which is another way in which it can make it more difficult to lose weight and to maintain what is lost.
Other Hunger Hormone Effects on the Body
Some studies looking into ghrelin have found that it also affects other functions of the body that don’t necessarily sound like they are connected to weight control, but that have a massive impact on the ease with which weight is lost and maintained. For instance, the hunger hormone can also affect an individual’s:
- Sleeping and waking cycle (circadian rhythm)
- Sense of taste
- Reward-seeking behaviors and reward processing
When you think about it, these ghrelin effects don’t take long to associate with weight management struggles. It’s far more difficult to achieve weight control when we’re not sleeping restfully, aren’t fully satisfied by the flavor of foods, and when food or alcohol misuse behaviors become a regular occurrence.