Do hormones play a role in hunger? Yes they do! While there are numerous hormones involved with hunger and fullness (including leptin, insulin, neuropeptide Y among others), one of the main hunger hormones is grehlin. Grehlin is a hunger hormone that is released by the gastrointestinal tract, primarily the stomach. One of grehlin’s main roles is to stimulate or increase hunger after being without food, such as between meals, or just prior to normal eating times.
Grehlin also prepares the stomach for food intake by stimulating the release of stomach acid which aids in food digestion as well as helps with gastric motility or movement. Gastric motility helps food move food through the digestive tract.
Interestingly, grehlin levels typically rise between meals the longer the duration without food, but also by the anticipation of food. Meaning, if you normally eat every 2 hours, you train your body to expect food and grehlin levels rise stimulating your appetite every 2 hours. On the flip side, if you eat every 4 hours, your grehlin levels will rise just prior to eating after about four hours. What does this mean? We can literally retrain our gastrointestinal system to stimulate our appetite by eating more or less frequently.
In addition, this is possibly why some individuals feel the urge to eat more frequently and others less frequently. I have some clients that don’t eat between meals whereas others want to eat frequently between meals. In addition, some individuals are not hungry in the morning, whereas others eat soon after rising.
Is that where cravings come from? Grehlin secretion preparing your body for food it expects to receive? From a physiologic perspective, in many cases, yes. If you always eat at a certain time of the day, your body will start the digestive process and release ghrelin,which feels like a craving.
While hunger cues are initiated by physiologic cues like grehlin, hunger cues may also be triggered by emotional or environmental cues. For example, if you always eat when stressed, bored, angry or tired for example, your body may anticipate food by one of those specific cues, release grehlin, which then stimulates hunger. You may also start the release of grehlin by being in the kitchen, simply by seeing food.
In addition, poor or reduced sleep time seems to increase grehlin levels as well. That’s why it’s important to strive for 8 hours of sleep each day. Adequate sleep may lower grehlin levels, leading to reduced hunger.
What can we do with this information about ghrelin? Can we retrain our grehlin production to eat healthier and when truly hungry? Yes. If you make a decision to not eat every two hours, but instead every four hours for example, your body will stop releasing grehlin at 2 hour intervals, but rather 4 hour intervals over time. If you stress eat, you can stop the grehlin release, by not stress eating. Certainly, not eating when stressed or bored can be quite difficult for some as it takes strategy, practice and persistence to carve out new habits.
It takes time and patience, but the body will ultimately adjust.
There are also a variety of other hunger hormones as discussed previously including leptin, neuropeptide Y among others, however for weight loss and keeping the weight off, grehlin is by far the most important one.
Have a healthy day!