Hunger hormone ghrelin: How it affects your appetite & weight

Key Points

• Ghrelin is your body's natural hunger signal, increasing before meals and decreasing after eating.
• Beyond hunger, ghrelin affects metabolism, growth hormone release, and several other body functions.
• Sleep, stress, diet composition, and meal timing all influence your ghrelin levels.
• Understanding how ghrelin works can help you manage hunger and improve your weight management efforts.

Hunger often seems like a straightforward concept: your body needs food to function, so you experience hunger when you're running low on energy (calories).

But you probably already know that hunger is actually more complicated than it seems. Ever feel like you had a big enough meal only to be hungry an hour later? Feel like you can’t get your hunger under control?

Hunger is influenced by a number of hormones, and the hunger hormone ghrelin is one of the key players in hunger.

But what is ghrelin, and how does it work? If it influences hunger, what role does it play in weight loss?

Let's explore more about the hunger hormone ghrelin.

What is ghrelin?

Ghrelin is known as the hunger hormone, influencing food intake, fat distribution, and growth hormone release. Ghrelin is a hormone produced by the gut. 

Ghrelin receptors are in the brain, in the hypothalamus. This area of the brain regulates appetite.

But ghrelin does a lot more than just regulate appetite. It also stops insulin from being released, decreases heat in the body to regulate energy expenditure, prevents muscle atrophy, regulates bone formation, and is even involved in surviving heart attack (myocardial infarction). Ghrelin also plays a role in cancer development.

How does ghrelin work?

Your ghrelin levels rise and fall throughout the day:

• Ghrelin travels through the bloodstream to the brain, where appetite is regulated by ghrelin receptors and more.
• When the body needs food, ghrelin levels increase, resulting in hunger and causing you to seek out food.
• After eating, ghrelin levels decrease, signaling a sense of satisfaction.

Your stomach releases ghrelin when it’s empty or mostly empty. Ghrelin levels are typically highest right before mealtimes.

Through this brain-gut connection, ghrelin can also promote body fat storage (which is necessary for energy homeostasis but can become an issue in excess), stimulate the release of growth hormones, aid in digestion, and control insulin release to improve insulin sensitivity.

What are other hunger hormones?

“Ghrelin, which is produced in the stomach, is the hunger hormone that signals to our brain when it is time to eat,” says Rosemary Rodriguez, RD. “Two other hormones, leptin, made from fat tissue, and cholecystokinin (CCK), produced in the small intestine, signal to our brain when our body feels satisfied after eating.”

Leptin

Leptin is the satiety hormone.

• Leptin communicates with the brain that the body has enough food (energy) stored and doesn't need any more.
• After receiving this signal, you are likely to stop eating and feel full.
• Higher levels of leptin reduce appetite and increase energy expenditure (calories burned).
• Low levels of leptin stimulate appetite, signaling hunger.

As you can see, leptin and ghrelin work in opposition to one another, with one increasing while the other decreases, and vice versa.

Insulin

Insulin plays a crucial role in regulating blood sugar and interacts with ghrelin. High insulin levels can lower ghrelin, potentially reducing hunger in the short term.

However, insulin resistance (common in people with type 2 diabetes or prediabetes) may disrupt this relationship, affecting normal hunger signals.

GLP-1 & satiety hormones

Several other hormones, including GLP-1 (glucagon-like peptide-1), PYY (peptide YY), and CCK (cholecystokinin), also play important roles in signaling fullness after meals.

Diabetes and weight loss medications like semaglutide (Wegovy, Ozempic) and tirzepatide (Mounjaro, Zepbound) work by mimicking GLP-1, helping to reduce appetite and promote feelings of fullness.

What influences ghrelin levels?

Ghrelin peaks when the body needs more energy – food – and decreases when the body has reached "energy homeostasis," or an adequate food intake.

However, given that ghrelin can increase food intake and may play a role in body weight, what else can influence ghrelin levels?

Low ghrelin

Ghrelin is actually lower in people with obesity. This may be surprising, given that people with severe obesity usually have an excessive food intake, but hormone and metabolic research shows that this may mean that obese people's bodies are more sensitive to ghrelin.

As such, obese people may feel hungrier with lower levels of ghrelin than others. In fact, a gene related to obesity, obestatin, has been found to essentially make ghrelin more powerful, leading to higher food intake and body weight without actually increasing ghrelin levels.

This hormone and ghrelin are also associated with type II diabetes, indicating how closely tied to metabolism ghrelin can be.

Low ghrelin is also associated with other gastrointestinal diseases, including:

• Irritable bowel syndrome (IBS)
• Functional dyspepsia
• Chronic gastritis
• H. Pylori infection

Gastric bypass surgery also leads to decreased ghrelin levels, helping patients continue to lose weight after surgery.

High ghrelin

Again, high ghrelin levels are not associated with high body weight. In fact, excessive calorie restriction can lead to higher ghrelin levels.

Other conditions associated with high ghrelin levels include:

• Anorexia nervosa
• Celiac disease
• Inflammatory bowel disease (IBD)
• Prader-Willi syndrome

So, while many people blame their weight gain on their hunger and ghrelin levels, it's unlikely that ghrelin itself is the cause.

That said, ghrelin levels do usually rise as you lose weight. This is one reason why maintaining weight loss can be challenging – your body is actively fighting against it by making you hungrier. The good news? Your body eventually adjusts to your new energy intake (daily calories) and your hunger levels decrease.

Can I lower my ghrelin levels?

No particular foods raise or lower ghrelin levels. You can maintain balanced circulating ghrelin levels by maintaining a healthy energy balance (ratio of food intake to activity level) and a balanced lifestyle.

Keep in mind that ghrelin is not the enemy! It is an essential hormone that influences much more than just hunger.

Even if you want to lose weight, ghrelin is not something that can be easily controlled, nor is it the likely cause of increased food intake.

Instead, focus on appetite regulation and eating the right amount for your goals.

Symptoms of hunger hormone imbalance

Ghrelin and other hunger hormones like leptin can be out of balance if your metabolism is off. Symptoms of this imbalance can include:

• Feeling hungry all the time
• Overeating
• Difficulty feeling full
• Intense cravings
• Insulin sensitivity or resistance
• Metabolic syndrome

If you feel like your eating habits or appetite signals have changed drastically, talk to your doctor. You may be insulin-sensitive or be experiencing issues with glucose regulation.

How does ghrelin influence weight?

While ghrelin does not cause weight gain, it does play a role in body weight.

Ghrelin often increases at the start of a diet as your body adjusts to your new food intake levels. This is why you often feel hungrier when you first start eating less. However, your body typically adjusts as you lose weight.

Additionally, ghrelin stimulates fat storage. This means that it can signal to maintain fat mass as a protective measure during weight loss. This is why weight loss can be so challenging – your body has evolved to hold onto fat to protect against starvation.

But don't worry: as you adjust to your new energy balance, the weight will come off.

How to manage hunger levels

If you're finding it challenging to manage your hunger levels, you're not alone. Hunger is both emotional and physical. Feelings can drive us to eat just as much as ghrelin does. And when you're trying to lose weight, hunger can feel like the biggest battle.

“I encourage clients to factor hunger hormone functionality into their dietary approach by tapping into their mind-body connection, if it feels safe to,” says Rosemary Rodriguez, RD. “Know that intuitive eating or mindful eating is possible whether it is your first time tuning into your mind-body connection, or if you are relearning this connection again.”

It's important to remember that hunger is not the enemy. Ghrelin stimulates hunger when your body needs food – and you always need to eat, no matter what your weight loss goals are.

Here are some tips to manage hunger levels when pursuing weight loss:

• Eat balanced meals. You are much likelier to feel satisfied for longer when each meal is made up of complex carbohydrates (like whole grains), healthy fats, and plenty of protein.
• Eat at consistent times. Your body has a circadian rhythm for more than just sleep. The schedule at which you are exposed to light, food, and more all influence this rhythm. Your hunger hormones benefit from consistent meal times. This includes overnight fasting, or your non-eating window between going to sleep and eating your first meal the next day.
• Avoid yo-yo dieting. Similarly, rapidly changing your food intake with periods of restriction can wreak havoc on your hunger hormones. Your body likes to be in homeostasis, and swinging between extremes can cause immense internal stress and lead to other issues down the line.
• Get enough movement. Exercise is important not just for heart function but for hunger levels too. It helps your body process the food it has already eaten and creates an optimal energy balance. Cardiovascular exercise can help prevent heart attack (myocardial infarction), improve insulin resistance and diabetes, and regulate hunger.

Achieve your weight loss goals with a registered dietitian

If you are struggling to manage your appetite while losing weight, one of the best ways to find a sustainable path forward is by working with a registered dietitian.

A qualified dietitian can assess your current food intake, understand your hunger levels and eating habits, and use all that information to create a completely custom meal plan that works with your lifestyle while helping you meet your health and body weight goals.

They can demystify the weight loss process and even explain as much as you want to know about hunger hormones to empower you with the knowledge you need to achieve your goals.

Finding a qualified dietitian is easy with Fay. You can find weight loss dietitians here and input your health insurance information to find providers covered by your health insurance.

With Fay, your nutrition counseling services could be as low as $0.

Start working with a weight loss dietitian today.

The views expressed by authors and contributors of such content are not endorsed or approved by Fay and are intended for informational purposes only. The content is reviewed by Fay only to confirm educational value and audience interest. You are encouraged to discuss any questions that you may have about your health with a healthcare provider.