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 ghrelin.
⸻
What is Ghrelin?
Ghrelin is a hunger hormone that is released by the gastrointestinal tract, primarily the stomach.
One of ghrelin’s main roles is to stimulate or increase hunger after being without food, such as between meals, or just prior to normal eating times.
Ghrelin also prepares the stomach for food intake by:
• Stimulating the release of stomach acid, which aids in digestion
• Helping with gastric motility (movement of food through the digestive tract)
⸻
How Ghrelin Levels Change
Interestingly, ghrelin levels typically rise between meals the longer the duration without food, but also by the anticipation of food.
• If you normally eat every 2 hours, you train your body to expect food, and ghrelin levels rise stimulating your appetite every 2 hours.
• If you eat every 4 hours, your ghrelin levels will rise just prior to eating after about 4 hours.
What does this mean? We can literally retrain our gastrointestinal system to stimulate our appetite by eating more or less frequently.
This may explain why some individuals feel the urge to eat more frequently while others eat less often. Some clients don’t snack between meals, whereas others want to eat frequently. Likewise, some people are not hungry in the morning, while others eat soon after rising.
⸻
Ghrelin and Cravings
Is that where cravings come from—ghrelin 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.
⸻
Beyond Physiology: Emotional & Environmental Cues
While hunger cues are initiated by physiologic signals like ghrelin, they may also be triggered by emotional or environmental cues.
For example:
• Stress, boredom, anger, or fatigue may trigger ghrelin release
• Simply being in the kitchen or seeing food may spark hunger
⸻
Sleep and Ghrelin
Poor or reduced sleep time seems to increase ghrelin levels as well.
That’s why it’s important to strive for 8 hours of sleep each day. Adequate sleep may lower ghrelin levels, leading to reduced hunger.
⸻
Can We Retrain Ghrelin?
What can we do with this information about ghrelin? Can we retrain our ghrelin production to eat healthier and when truly hungry?
Yes. For example:
• If you change from eating every 2 hours to every 4 hours, your body will stop releasing ghrelin at 2-hour intervals and adjust over time.
• If you stress eat, breaking that pattern can reduce ghrelin release linked to stress.
Of course, not eating when stressed or bored can be difficult. It takes strategy, practice, and persistence to carve out new habits.
⸻
Final Thoughts
It takes time and patience, but the body will ultimately adjust.
There are also a variety of other hunger hormones (leptin, neuropeptide Y among others). However, for weight loss and keeping the weight off, ghrelin is by far the most important one.
Have a healthy day!