Get To Know Ghrelin: The Hunger Hormone
Ghrelin, a hunger hormone, is produced in the stomach and plays many roles in hunger.
Our body is an incredible machine, making hormones that are responsible for regulating sleep, increasing and decreasing hunger, making us feel full, producing more sex hormones, the list goes on and on! Ghrelin is one of several key players our body produces to regulate hunger.
So many clients ask us how to reduce their appetite to help support them in reaching their weight loss goals and there are many actions you can take to do that! One of them is simply educating yourself on what hunger hormones do in your body and how you can support your body in increasing or decreasing depending on your goal. Ghrelin is one of several hormones that play a role in regulating hunger, for the sake of this article, let’s dive into this specific hormone.
So, What Is Ghrelin?
This hormone, pronounced ghrel-in, is also known as the “hunger hormone” due to its an important role in stimulating appetite, which increases our food intake and helps promote fat storage. In a nutshell, this hormone sends a signal to your brain, “hey, I’m super hungry, let’s eat!”. (1) (2) When you say this hormone out loud, ghrelin, the way you can remember what this hormone does is to think of a tiger “grrr-ing” like it’s hungry for food!
As you may be reading this, if you’re on a weight loss journey, you may think that ghrelin is bad — who wants a hormone that increases food intake and promotes fat storage if that’s the opposite of your goal? Well, all our hormones have a time and place and specific use and benefit in the body, it’s more about knowing what diet choices you can make and lifestyle actions you can take to help hack this hormone in the way that benefits your unique long-term health goals.
What does ghrelin do?
Stomach cells are primarily involved and responsible for producing ghrelin, but the pancreas and small intestine also release small amounts of ghrelin — all act to stimulate hunger and secrete growth hormone. (3)
Ghrelin and the function of how it’s expressed and produced involve both physiological and pathological conditions — health conditions, nutrients, other hormones, and the autonomic nervous system play a role in the regulation of ghrelin and produced of it in the digestive system. (4)
Glucose inhibits ghrelin secretion (4) A few studies both in humans and in rats showed that when subjects were given glucose (remember, this is sugar!), the amount of ghrelin in the bloodstream decreased after 3o minutes. (5) (6)
To summarize, when ghrelin is produced in the digestive system (mainly the stomach), it travels in the bloodstream, reaches the brain (hypothalamus which regulates hormones and appetite) which sends a signal which increases appetite so you become hungry and eat more food. (7) (8) (9) (10)
If you’re interested in this topic, you might also want to check out the following articles: Understanding The Gut-Brain Connection, What Are Prebiotics, How Stress Affects Digestion, Tips For Reaching A Healthy Weight, and 10-Plant Proteins You Should Be Eating.
How To Regulate Ghrelin
We can’t assume that everyone wants to or is on a weight loss journey, there’s a large part of the population that also struggles with gaining weight healthfully. For that matter, let’s take an unbiased look at both of the ways our body can regulate the hunger hormone ghrelin.
Also, as a sidebar, remember that there are many complicated factors that go into regulating and impacting appetite, for the sake of this article, we’re just looking at the hormone ghrelin but there are many others involved. If at any point you need support in learning more about your relationship to food and hunger, check out our Coaching Clinic for more opportunities to get supported.
Higher Ghrelin Levels Increase Appetite
Naturally, before we eat or about a few hours after we eat, ghrelin levels will be highest. That’s because those hormone levels haven’t reduced with the intake of food! Remember that signal that’s sent to our brain (our hypothalamus) that tells us to go eat food?
Research shows that those who are overweight, obese, or morbidly obese have lower fasting levels of the hormone ghrelin versus those who are at a normal weight range. The signal to the brain that tells the body to reduce ghrelin while or right after eating to signal that the body is “full” is not as strong (because ghrelin decreases only slightly) which may lead to overeating in people who are obese versus those who are at a normal weight range. (11) (12) (13)
Lower Ghrelin Levels Reduce Appetite
If your goal is to reduce appetite, eating a diet rich in whole food fiber from fruits, vegetables, legumes, and whole grains along with healthy fats and protein can help lower levels of ghrelin. Protein, for example, eaten at every meal can promote the full factor we’re all searching for post-meal (i.e. protein increases satiety) and can reduce levels of ghrelin. (14) (15) (16)
Taking omega-3 fish oils or overall increasing your diet in more omega-3 rich foods can help support reducing appetite (19)
In addition to eating a whole food diet rich in fiber, protein, and healthy fats, exercise has also been shown to help decrease ghrelin levels. Specifically, a few studies showing that engaging in high-intensity interval training (HIIT) decreased ghrelin and increased growth hormone (which can support weight loss efforts amongst other things it’s responsible for). (17) (18)
In addition, making sure you’re sleeping enough and having high-quality sleep can impact the hormones that regulate hunger including ghrelin. (20) (21) Another important lifestyle factor along with getting enough sleep and exercise is also managing stress. Engaging in stress management can also help reduce ghrelin levels and support weight loss. (22)
What Your Body Does On A Diet
Have you ever dieted before? What I mean by that is consciously restricted calorie intake in order to follow a strict diet, follow a nutrition plan, or other means to reach a goal proposed by calorie restriction? If you have, then you know how difficult sticking to a plan like that is for a long period of time.
It’s not all about willpower or determination to stick to a low-calorie diet, your hormones, like ghrelin play a huge role in how your body reacts to these shifts in calorie intake. Ghrelin increases when you restrict calories.
Let’s say that again, the hunger hormone that stimulates appetite increases when the body is in a state of eating a low-calorie diet. You might think your hormones are working against you, and well, in a way, yes but it’s only to our survival benefit and because of the armor we’ve created since the evolution of biology and helping us maintain a healthy weight.
Engaging in restricting calories, yo-yo diets, or crash diets will increase the levels of ghrelin in your body, which again, makes you hungry and all the more difficult to stick to a low-calorie diet.
Unless you’re trying to gain weight, overeating in the caloric sense, causes ghrelin levels to decrease.
The NS Verdict
Ghrelin isn’t a bad hormone as much as it may sound even if weight loss if your goal — it’s part of our biology and has a specific purpose to help us regulate hunger.
If you’re someone who is looking to find support in weight loss or weight gain, then applying these tips and what the evidence shows may help, but always work with a Registered Dietitian to find a specific and unique-to-you plan. We’re always here to support you at Nutrition Stripped, so head to our Coaching Clinic page to learn more about becoming a client.
Become an NS Society® Member
A monthly membership to support you in making healthy habits with monthly video classes and member perks exclusive to the NS Society® community — led by Dietitian and Founder of NS, McKel Hill, MS, RDN, LDN.