Which hormone reduces appetite and increases the feelings of being full when it is released into the bloodstream?

How they affect your appetite and your weight

If there was a hormone in your body whose chief job was to make you feel hungry, most of us probably wouldn't be too keen on it. (I don't know about you, but having a healthy appetite has never been a problem for me.) But if there was a hormone that decreased our appetites, we'd order buckets of it!

Well, let me introduce you to some hormones that do just those things: the "hunger hormones," leptin and ghrelin.

Leptin is a hormone, made by fat cells, that decreases your appetite. Ghrelin is a hormone that increases appetite, and also plays a role in body weight.

Levels of leptin -- the appetite suppressor -- are lower when you're thin and higher when you're fat. But many obese people have built up a resistance to the appetite-suppressing effects of leptin, says obesity expert Mary Dallman, PhD, from University of California at San Francisco.

Here's what we know so far about the "hunger hormones" and what we can do to help control our appetites.

What We Know About Ghrelin

Ghrelin, the appetite increaser, is released primarily in the stomach and is thought to signal hunger to the brain. You'd expect the body to increase ghrelin if a person is undereating and decrease it if they are overeating. Sure enough, ghrelin levels have been found to increase in children with anorexia nervosa and decrease in children who are obese.

German researchers have suggested that ghrelin levels play a big role in determining how quickly hunger comes back after we eat. Normally, ghrelin levels go up dramatically before you eat; this signals hunger. They then go down for about three hours after the meal.

But some researchers believe that ghrelin is not as important in determining appetite as once thought. They think that its role in regulating body weight may actually be a more complex process.

What We Know About Leptin

Of the two hormones, leptin -- the appetite suppressor -- appears to be the bigger player in our bodies' energy balance. Some researchers think that leptin helps regulate ghrelin.

Leptin helps signal the brain that the body has enough energy stores such as body fat. But many obese people don't respond to leptin's signals even though they have higher levels of leptin.

In general, the more fat you have, the more leptin is in your blood. But the level varies depending on many factors, including when you last ate and your sleep patterns.

A study showed that rats that were given doses of leptin ended up eating less, but this effect lasted only about two weeks. It seems that the rats developed a resistance to leptin's appetite-cutting effects.

How to Control Hunger Hormones

Are there ways to control our "hunger hormones," and thus rein in our appetites? Possibly -- by avoiding high-fat foods.

When we eat, messages go out to various parts of our bodies to tell us we've had enough. But when we eat fatty meals, this system doesn't work as well, says Dallman. Eating fat tends to lead to eating more calories, gaining weight, and storing fat, Dallman says. Researchers have seen some of these effects after only three days of a high-fat diet.

But researchers have shown that either a diet rich in either "good" carbohydrates (like whole grains) or a diet high in protein suppresses ghrelin more effectively than a diet high in fat.

Something that might help (and certainly won't hurt) is to get enough sleep! In a study of 12 young men, sleep deprivation was associated with an increase in ghrelin levels, appetite, and hunger compared with when they slept 10 hours a night.

All in all, this adds to the huge amount of evidence showing that avoiding a high-fat diet is one of the keys to maintaining a healthy weight.

Ghrelin is a hormone mainly produced in the stomach when it is empty. It is also produced in the small intestine, brain, and pancreas.

Ghrelin travels through the bloodstream to the brain, where it acts on the hypothalamus. The hypothalamus is a part of the brain, which produces hormones that regulate hunger, mood, thirst, and many other important functions within the body.

Ghrelin is often referred to as the hunger hormone because its primary role is to regulate appetite. When ghrelin activates its receptor — growth hormone secretagogue receptor — it causes a person to eat more food and store extra fat.

In people who are trying to lose weight or who have recently lost weight, ghrelin levels are often higher, making it challenging to maintain weight loss.

For example, one study from 2020 looked at people with diabetes who participated in a 2-year weight management program. Participants who initially lost weight slowly regained it over the study duration. Researchers found that weight loss was associated with increased ghrelin levels and increased hunger, which might make it difficult to keep weight off.

Ghrelin can also signal the body to decrease brown fat thermogenesis. When this happens, the body burns less fat at rest. Brown fat is known for its thermogenic properties and ability to increase overall calories burned.

Studies show that ghrelin also affects a person’s sleep/wake cycle, taste sensation, and reward-seeking behavior.

As it plays a role in reward processing, many experts believe higher ghrelin levels can contribute to food and alcohol misuse.

Recently, researchers have discovered that ghrelin also has many functions in the body, including improving heart health, preventing muscle atrophy, and influencing bone metabolism.

It can also stimulate gastric acid secretion and accelerate gastric emptying.

Levels of ghrelin frequently change throughout the day and are primarily controlled by food intake. Ghrelin levels usually rise when the stomach is empty and decrease once a person has eaten.

Some studies show that people who have obesity have higher levels of ghrelin circulating. This can lead to a continuous state of hunger and make it difficult to lose weight.

However, research remains conflicted on this point. Yet a 2015 review suggests that ghrelin levels are low in people with obesity and even lower in people with obesity who also have a binge-eating disorder.

Dieting also has been known to stimulate ghrelin secretion. What is more, diets can also decrease leptin levels, which is known as the “satiety hormone.” Combined, this may make it difficult to lose weight and keep it off long term.

Interestingly, experts believe people who have undergone weight loss surgery have lower levels of ghrelin, which may make it easier to keep weight off.

In particular, one recent review found that ghrelin levels fall significantly following sleeve gastrectomy. Researchers believe this is because part of the stomach — the gastric fundus — where most ghrelin is produced is completely removed. However, the results of other studies are inconsistent for other weight loss procedures such as roux-en-y gastric bypass.

People with certain health conditions also tend to have elevated ghrelin levels.

People with obesity and Prader-Willi syndrome (PWS) have very high levels of ghrelin circulating, which may play a role in their constant sense of hunger and difficulty controlling weight.

Additionally, people with Hashimoto’s thyroiditis, anorexia nervosa, bulimia, and cachexia from illness tend to have higher hunger hormone levels.

Ghrelin levels also may be higher during periods of stress. Higher ghrelin levels are thought to have an anxiolytic effect on the body.

Although elevated ghrelin levels are commonly perceived as unfavorable and associated with increased appetite, certain individuals may benefit from higher ghrelin levels.

For instance, someone struggling to gain weight or with wasting syndrome may benefit from the appetite-stimulating effects of ghrelin.

Newer studies suggest ghrelin administration may potentially be helpful in patients with cancer cachexia because it can help reverse weight loss and protein breakdown in catabolic states. Although short-term ghrelin administration appears to be safe and well-tolerated, we need more studies on its effectiveness and safety before recommending it.

Animal research on how cannabis increases appetite by stimulating ghrelin production also appears to be promising to support its use in treating illness-induced anorexia.

Additionally, one human study in men with HIV found that tetrahydrocannabinol (THC), the psychoactive compound in cannabis, can stimulate ghrelin release.

Ghrelin levels may increase following weight loss. Decreasing levels of ghrelin in the body may help decrease a person’s appetite, prevent weight regain, or promote weight loss.

However, it is important to note that other studies highlight monitoring changes in ghrelin alone are not sufficient to predict weight gain following weight loss in most people. Behavioral, physiological, and environmental factors also play a role in weight regain.

A person who wants to naturally decrease ghrelin levels may want to try some of the following interventions.

Follow a healthy diet

People’s ghrelin levels tend to increase when on a diet and not eating enough calories. Avoiding an empty stomach and eating a nutrient-rich diet may help limit ghrelin secretion.

According to the Dietary Guidelines for Americans, 2020–2025, the main elements that make up a healthy dietary pattern include:

  • vegetables of all types
  • fruits, especially whole fruit
  • grains, at least which half are whole grains
  • low fat dairy
  • lean protein
  • oils, such as olive oil and those naturally occurring in nuts and fatty fish

Some foods may also decrease ghrelin levels. In one older study, researchers discovered that fiber-rich foods could reduce ghrelin levels.

Another study looked at 21 men who were either given a bagel or eggs for breakfast. The group who ate eggs for breakfast had decreased ghrelin levels than those who ate bagels.

Get adequate sleep

Poor sleep patterns are tied to increased ghrelin levels and decreased leptin levels, leading to increased appetite and hunger. For better sleep, aim to get a minimum of 7 hours of sleep in a 24-hour period.

Eat more protein

Consuming high protein meals and snacks can help promote satiety and reduce ghrelin levels. In fact, many meal-related studies have shown significant reductions in hunger and increased fullness following high protein meals.

Researchers suggest getting between 1.2-1.6 grams of protein per kilogram of body weight per day or 25–30% of daily calories to promote weight management and appetite suppression. Most people can follow a high protein diet by eating chicken breast, beans, lentils, low fat dairy, and shellfish.

Limit stress

Although removing stress altogether is near impossible, studies show that high levels of chronic stress can lead to elevated ghrelin levels. In addition to signaling hunger, ghrelin may affect brain function. The exact mechanism remains unclear, and mixed findings make it difficult to draw conclusions about ghrelin’s role in stress.

Some animal studies suggest it may reduce anxiety and have antidepressant-like properties, while other studies suggest it may promote these behaviors.

Regular physical activity, adequate sleep, and practicing yoga or meditation can help minimize stress.

Exercise

Research surrounding the effect of exercise on ghrelin levels remains conflicting. In one 2021 review, researchers found that acute exercise suppresses ghrelin production. However, they also found that long-term exercise programs may have the opposite effect and increase ghrelin production.

The exact mechanism behind these effects remains unclear, but researchers believe it is likely due to elevated blood flow redistribution and weight loss from exercise.

Ghrelin is known as the hunger hormone due to its key role in appetite regulation. High levels of ghrelin lead to an increase in appetite and food intake. However, the body needs ghrelin because it is involved in many processes. These include improving heart health, influencing bone metabolism, and preventing muscle breakdown.

A person who wishes to naturally reduce ghrelin levels in the body may consider eating a healthy, fiber-rich diet, consuming adequate protein, exercising, getting enough sleep, and minimizing stress.

In contrast, someone with illness-induced anorexia or difficulty gaining weight may benefit from higher ghrelin levels to promote hunger and weight gain.

Which hormone reduces appetite and increases the feelings of being full?

Leptin is a hormone your adipose tissue (body fat) releases that helps your body maintain your normal weight on a long-term basis. It does this by regulating hunger by providing the sensation of satiety (feeling full).

Which hormones decrease appetite and reduce food intake?

Leptin is a hormone, made by fat cells, that decreases your appetite. Ghrelin is a hormone that increases appetite, and also plays a role in body weight. Levels of leptin -- the appetite suppressor -- are lower when you're thin and higher when you're fat.

What is the hormone that makes you feel full?

Ghrelin and leptin are two of many hormones that control your appetite and fullness. They're involved in the vast network of pathways that regulate your body weight. Leptin decreases your appetite, while ghrelin increases it. Ghrelin is made in your stomach and signals your brain when you're hungry.

What hormone is responsible for appetite?

Ghrelin is a multifaceted gut hormone which activates its receptor, growth hormone secretagogue receptor (GHS-R). Ghrelin's hallmark functions are its stimulatory effects on food intake, fat deposition and growth hormone release. Ghrelin is famously known as the “hunger hormone”.