7 Hormones That Control Appetite and Hunger

Kelly Harrington, MS, RD

Mar 28, 2023

10 min read

Updated: 11 minutes ago

7 Hormones That Control Your Appetite and Hunger

Your appetite isn't controlled by one hormone. It's regulated by an interconnected system of hormones and neural signals that communicate between the gut, brain, pancreas, and fat tissue.

There are effective ways to support the systems involved in appetite and hunger through nutrition, sleep, movement, and other lifestyle factors. If you want to lose weight or maintain your body weight, understanding how these hormones influence hunger, appetite, and satiety can help you better understand your body's signals, which is so important to your success.

Let's look at the key hormones involved in hunger, appetite, and satiety, and what nutrition and lifestyle can realistically do to support them.

Ghrelin: The Hunger & Snacking Hormone

Ghrelin is often called the hunger hormone because it activates hunger and stimulates your appetite. It relates to when you get hungry, and also drives the feeling of hunger levels. When I hear the word ghrelin, I think of “gremlin,” and in my opinion, that’s a great way to describe this little hormone monster!

Under fasting conditions, ghrelin is produced primarily by the stomach and circulates in the bloodstream. Ghrelin also sends signals to the brain via the vagus nerve to communicate hunger, food intake, and energy balance.

Ghrelin's main role is to stimulate your appetite by telling you, “Time to eat!” Ghrelin levels typically rise before meals and fall after eating, making it an important part of the body's short-term hunger signaling system.

Do you find yourself thinking about a specific food at a certain time of day? This is because of Ghrelin! Research shows ghrelin is like a hormonal clock that follows daily rhythms, making you want to eat at particular times.

What Causes Ghrelin to Rise in the Body?

An increase in ghrelin is influenced by several factors, including a drop in glucose levels in your bloodstream, fasting, energy availability, circadian rhythms, and habitual meal patterns. If glucose drops too low, ghrelin is produced and it makes you want to eat.

Just as levels of glucose rise and fall throughout the day, levels of ghrelin also fluctuate over the course of the day —they rise before meals and fall rapidly after ingestion. Ghrelin levels fall to their minimal level within 1 hour after eating.

This is one reason hunger isn't simply a matter of willpower. Your body has biological systems designed to increase the drive to eat when it senses that energy is needed. This little monster can be blamed for those uncontrollable urges to snack and is a key player in body weight changes over the long term, and unfortunately, not in a good way…

Ghrelin and Weight Loss

Here's one of the most interesting things about ghrelin: losing weight can increase the body's drive to eat. Weight loss significantly increases ghrelin levels, regardless of the weight loss method (ie: calorie restriction, illness, etc.). This seems to be the reason so many people have such a hard time not only losing weight but also keeping it off.

A 2025 meta-analysis that included 127 studies found that weight loss through calorie restriction, exercise, or a combination of the two was associated with an increase in total ghrelin. The researchers also found that greater weight loss was associated with a greater increase in total ghrelin.

This may be one reason maintaining weight loss can be challenging. Your biology doesn't necessarily become indifferent to the weight you've lost. Changes in appetite-related hormones can create a physiological drive toward eating and restoring lost energy stores.

That doesn't mean weight regain is inevitable. It means increased hunger after weight loss can have a biological component and isn't simply a failure of willpower.

Tips to Manage Ghrelin Levels:

1. One strategy to keep the ghrelin system off-kilter is to stay off a set eating schedule. Rather than eating breakfast, lunch, and dinner at the exact same time every day, consider changing up your meal times by just 45 minutes sooner or later on a regular basis.

2. As helpful as it may be to keep your eating schedule mixed up, Don’t skip meals. Skipping meals leads to an increase in ghrelin levels, with a nearly twofold increase immediately before each meal. If that won’t cause you to overeat, I don’t know what will! This goes the same for under-eating of any kind.

3. Get Enough Sleep! Ghrelin has been shown to increase in our bodies with sleep disturbance. In fact, one study shows even just ONE NIGHT of sleep deprivation can cause a rise in levels and an increased appetite. Leptin is also affected by sleep deprivation. No wonder there’s a connection between lack of sleep and obesity.

4. Eat Enough Protein. Even when someone is restricting their calorie intake, eating a higher proportion of protein foods can help control their appetite.

Leptin: The Appetite Suppressor Hormone

Leptin is a hormone made by our fat cells and decreases our appetite, hence the reason I call it the appetite suppressor. Leptin is needed for long-term energy balance. This is key for weight maintenance.

Leptin is also involved in the signaling a sense of satiety, which is the feeling of fullness after eating. Leptin tells the brain there are sufficient calories coming in, and there is enough fat in storage so no more is needed. This helps prevent overeating, and in the big picture, it’s an important regulator of energy balance. Leptin also boosts our metabolism by encouraging the body to burn the calories we have eaten.

Under desirable circumstances, as the levels of leptin rise in our bloodstream (fullness), ghrelin levels fall (hunger) and vice versa. This makes you feel full and satisfied after a meal.

In overweight or obese individuals, unfortunately, the opposite begins to happen -- they usually have very high levels of leptin in their blood. In fact, one study found leptin levels in obese people were 4 times higher than in people of normal weight. Unfortunately, their leptin signaling system doesn't work properly, which is called leptin resistance. The message to stop eating doesn’t get through to the brain, so it doesn’t realize you have enough energy stored, so you keep eating.

Two potential causes of leptin resistance are chronically elevated insulin levels and inflammation in the hypothalamus.

How to Support Healthy Leptin Levels:

1. Avoid inflammatory foods: Limit foods that cause inflammation, especially sugary foods, and drinks, and trans fats.

2. Eat certain foods: Eat more foods that support healthy inflammatory levels, such as fatty fish.

3. Exercise regularly: Moderate activity can improve leptin sensitivity, especially lower-body strength training.

4. Get enough sleep: Studies have shown insufficient sleep leads to a drop in leptin levels and increases appetite.

Peptide YY (PYY): A Gut Hormone that Promotes Satiety

I call this the "wait 20 minutes" hormone. Putting food in your stomach lowers ghrelin levels, but that doesn't necessarily stop you from eating more. There is a huge difference between the phenomenon of satiety versus the phenomenon of lack of hunger. Ghrelin will reduce hunger, but that often won't keep you going back for more or heading to the pantry or refrigerator to look for something else to eat.

The signal for satiety — the switch that turns off the meal and turns on satiety — is a hormone called peptide YY. After food moves through the small intestine, PYY is triggered and released into the bloodstream, which binds to receptors in the hypothalamus of the brain and tells you that you're full. The problem is between the stomach and the PYY cells are twenty-two feet of intestines. It takes time for the food to get there and generate the PYY signal.

How to trigger PYY more quickly?

1. Insoluble fiber! It will make the food move through the intestines faster which will generate the satiety signal sooner.

2. Give it 20 minutes! The Japanese have a saying, "Eat until you are 80 percent full." This is very difficult to do in America. The key is to wait twenty minutes for the second portion. Also, make sure your first portion is an appropriate size — even if you don't go back for seconds, you're going to do damage if you've supersized your meal.

Cholecystokinin (CCK): A Hormone That Helps End a Meal

Cholecystokinin is potent in decreasing your appetite and reducing your levels of hunger for a period of time. It has been studied for well over 20 years. It is produced by cells in your gastrointestinal tract and its release is governed by neurons that detect what's in the gut, and by certain elements of the mucosal lining of the gut.

The gut microbiome's influence on appetite and satiety is not common knowledge, yet with so many people trying to lose weight, it is crucial knowledge to have. Our gut microbes are directly participating in an appetite regulatory circuit by releasing bioactive molecules that tell us whether we are full or still hungry.

Dietary Factors That Stimulate CCK Release in the Gut:

1. Omega-3 Fats and Conjugated Linoleic Acid CCK is stimulated by omega 3 fatty acids (omega-3 from algae, krill, fish oil) and conjugated linoleic acid (CLA) which then reduces, or at least blunts, appetite to the point where you don't overconsume food.

2. Amino Acids, especially Glutamine

Eating protein is vital for stimulating the release of CCK! Protein is broken down into amino acids, and GLUTAMINE is one particular amino acid involved in CCK release. Once a threshold level of amino acid and glutamine has been reached in the stomach, CCK is released and it helps reduce the activity of the neurons that promote feeding. Glutamine may even help reduce sugar cravings. Just know, glutamine can slightly increase blood sugar levels at the same time.

3. Fiber

Include Soluble Fiber because it decreases hunger and triggers the satiety hormones. In one study, when men ate a meal containing beans, their CCK levels rose twice as much as when they consumed a low-fiber meal.

Highly processed foods and emulsifiers in processed foods Interfere with CCK release.

Emulsifiers found in highly processed foods may extend the food's shelf life, but they also strip away the mucosal lining of the gut and actually cause the neurons in the gut to retract deeper into the gut. This means "fullness" signals like CCK never get triggered or deployed which results in wanting to eat far more processed foods. The signal that shuts down hunger isn't turned on as it should be, and ultimately, this leads to weight gain.

Common emulsifiers, found in highly processed foods, include soy lecithin, mono- and diglycerides, polysorbates, and propylene glycol esters. In addition, neurons in the gut sense sugar and send a subconscious signal up to the brain via the vagus nerve. Those neurons trigger the release of dopamine, which makes you crave more of that food. Ultimately, this is a complex process, but it really goes to show that a calorie IS NOT a calorie.

Glucagon-Like Peptide-1 (GLP-1): The Satiety & Incretin Hormone

Glucagon-like peptide-1 (GLP-1) is a hormone produced in your gut when nutrients enter the intestines. GLP-1 plays a major role in keeping blood sugar levels stable, and also makes you feel full.

Suggestions to Increase GLP-1:

1. Eat plenty of protein: As with the other hunger hormones, eating high protein foods like fish, whey protein, and yogurt have been shown to increase GLP-1 levels and improve insulin sensitivity.

2. Eat Foods that Support Normal Inflammatory Levels: Chronic inflammation is linked to reduced GLP-1 production.

3. Leafy greens: In one study, women who consumed leafy green vegetables like spinach and kale experienced higher GLP-1 levels and lost more weight than the control group.

Insulin: Promotes Fat-Storage Hormone

When you eat a carbohydrate or sugar-containing food, it is broken down into glucose and triggers the pancreas to release insulin. Insulin removes the glucose from the bloodstream and shuttles it to the appropriate tissues in the body. It is essential for keeping glucose levels within a certain range (healthy range: 70-100 ng/dL).

Why is it important glucose is kept at a particular level?

Because glucose triggers insulin, and insulin is the main fat storage hormone in the body. It tells fat cells to store fat and prevents stored fat from being broken down. This is less than ideal when you're trying to maintain your weight or promote weight loss.

Overeating — especially sugar, refined carbohydrates, and fast food — drives insulin resistance and increases insulin levels.

Tips to Normalize Insulin Levels and Improve Insulin Sensitivity:

1. Avoid Sugar as Much as Possible: High amounts of sucrose promote insulin resistance and raise insulin levels

2. Reduce Carbohydrates: A low-carb diet can cause an immediate drop in insulin levels.

3. Eat Your Protein, Fibrous Veggies, or Fat Before Your Carbs at a meal: The order in which you eat your macros does influence how much insulin is released into your bloodstream. Eating carbs first or early in the meal will give a steep rise in glucose (and therefore insulin).

4. Fill up on Protein: Protein has a small impact on blood sugar levels and therefore does not trigger a huge insulin release.

5. Include Plenty of Healthy Fats: Healthy fats, such as those from fatty fish, avocado, and olives do not impact blood glucose levels and can help lower fasting insulin levels.

6. Exercise Regularly: Blood glucose levels can be modulated very powerfully through movement, including just walking briskly, jogging, or cycling. The movement is especially beneficial either before, after, or during your meal. For example, taking a 30-minute walk after a meal will blunt your blood sugar levels in ways that are beneficial. Taking a walk an hour before you eat will also help blood sugar levels.

7. Get enough Magnesium: Magnesium supports sleep, and sleep is important for healthy blood glucose levels. People with insulin resistance are often low in magnesium, and magnesium supplements can promote normal use of insulin by the cells.

8. Drink Green Tea: Green tea may lower blood sugar and insulin levels.

9. Berberine: Supports healthy blood glucose levels. It can activate a certain pathway associated with fasting and low blood glucose levels.

Cortisol: The Stress-Appetite Connection Hormone

This stress hormone is a tricky one!! It's your short-term friend and your long-term enemy. Keeping cortisol low, which means keeping stress down, is difficult for many people. Stress-induced eating may be one of the toughest challenges to overcome. First, because it's not the stress, it's the response to stress and how fast the body is able to recover from the stress that matters.

Excess cortisol drives visceral fat, insulin resistance, and further food intake.

One simple, cheap, and effective way to reduce your cortisol is EXERCISE! Although exercise raises your cortisol levels while you're doing it (to mobilize glucose and free fatty acids for energy), it reduces your cortisol levels for the rest of the day. It burns off fat in your muscles to improve muscle insulin sensitivity, and in your liver to improve hepatic insulin sensitivity.

It is very clear leptin, ghrelin, and the five other hormones I mentioned, play major roles in energy balance and ultimately weight management. Looking at the big picture, I recommend eating real, brightly colored food (this means a lot of vegetables and some fruit), Eat enough fat and protein, Exercise regularly, and Sleep Well, and you’ll be on the right track.

With Love,

Kelly

Registered Dietitian Nutritionist