Ghrelin The "Hunger Hormone" What Does Ghrelin Do

You may have heard of the hormone Ghrelin, aka “the hunger hormone.” Understanding weight loss and the biological processes that your body goes through when trying to lose weight or gain muscle can get quite complex. We’re going to discuss how this multifaceted hormone works, and the role it plays in your metabolism.

What Is Ghrelin 

Ghrelin, aka “the hunger hormone”, is a gut hormone and the endogenous ligand for the growth hormone secretagogue receptor (GHSR). It was first discovered, in 1996, when the growth hormone secretagogue, MK-677 (Ibutamoren) was employed to clone the growth hormone secretagogue receptor (GHSR1a) [R]. Along with the observation that GHRP-6 induced activation of GHSR1, observational data suggested the presence of an unknown but endogenous ligand agonist for GHSR1 - one that might regulate systemic metabolism. In 1999, that ligand was discovered and identified. The 28 amino acid peptide was named ‘ghrelin’, a name originating from ‘ghre’, the Proto-Indo-European root of the word 'grow'.

Ghrelin stimulates the endogenous release of growth hormone through the pituitary gland. It controls appetite your sleep/wake cycle, taste sensation, and carbohydrate or glucose metabolism.

High levels of ghrelin are associated with increased hunger. Lower levels are associated with increased feelings of fullness. Ghrelin communicates to your brain when you are hungry, and its main function is to increase appetite.

Your hormones and metabolism will take time to adjust to changes in your diet, to not only lose weight, but to maintain weight loss over time.

How Does Ghrelin Work, What Does Ghrelin Do

Ghrelin is a gastrointestinal peptide hormone. Ghrelin’s main function is to regulate food intake and increase appetite. It’s produced in the stomach and secreted when the stomach is empty. It then enters your blood stream, which affects the hypothalamus in the brain, and stimulates the release of growth hormone and your appetite.

In fact, ghrelin has a complex variety of tasks within the regulation of hunger and metabolism.

Ghrelin regulates food intake, body weight, and glucose metabolism [R]. It also plays an active role in the modulation of sleep, taste sensation, and the suppression of brown adipose tissue (BAT) thermogenesis. The function of brown adipose tissue is to transfer energy from food into heat increasing energy expenditure. Ghrelin signaling decreases thermogenesis to regulate energy expenditure.

When you are dieting, or in a caloric deficit trying to lose weight, ghrelin levels typically rise and make you hungrier, while leptin levels, the fullness hormone fall. Metabolism is directly associated with ghrelin and leptin levels. Although weight loss requires a caloric deficit, cutting calories too low can tank your metabolic rate. This is why it’s crucial to slowly reduce food intake and work with a certified nutrition coach to ensure the best results.

How to Naturally Decrease Ghrelin Levels

The best and most effective way to reduce ghrelin levels, is through a healthy diet.

Diet culture and popular diet trends promote weight loss through to drastically cut calories and food elimination. Although a caloric deficit is necessary for weight loss, cutting calories to low, will inevitably increase ghrelin levels. Ghrelin levels will also be elevated.

Eating a nutrient rich diet, with foods that are healthy and maintain satiety will limit ghrelin secretion and curb hunger levels.

A healthy diet and eating pattern will consists of

  • Fruit and vegetables
  • Grains
  • Lean proteins
  • Healthy fats such as Omega-3s
  • Complex carbohydrates

Studies have found that fiber or complex carbohydrates, as well as protein reduce and regulate ghrelin levels [R, R].

Complex carbohydrates increase satiety and keep you feeling fuller for a longer period of time. Protein helps promote satiety and leptin levels, while reducing ghrelin levels. Most studies show increased feelings of fullness after eating high protein meals.  

Exercise will also naturally decrease ghrelin levels, by suppressing appetite. A systematic review published in the journal Sports Medicine found that ghrelin is suppressed during exercise, most likely due to blood flow redistribution and weight loss for acute and chronic exercise [R].

Common Questions About Ghrelin

When Is Ghrelin Released?

Ghrelin is released when the brain signals hunger. Ghrelin can be released through conditions, such as seeing pictures of food, inducing the sensation of hunger, in times of fasting, or when dieting. Ghrelin is released and secreted when the stomach is empty.

Where Is Ghrelin Produced?

Ghrelin is produced in the gut and is a peptide hormone, that transmits signals to the hypothalamus and pituitary gland.

What Does Ghrelin Do

The main functions of ghrelin, are its stimulatory effects on food intake, fat deposition and growth hormone release. 

What Stimulates Ghrelin

Excitation of the vagus nerve can stimulate ghrelin secretion. Ghrelin stimulation and levels frequently change throughout the day. Ghrelin levels rise when the stomach is empty and signal to the brain, when it’s time to eat. They will fall when you eat.

Ghrelin: Takeaway

Ghrelin plays a pivotal role in appetite, hunger, and energy metabolism. High levels of ghrelin can increase hunger and food intake. Ghrelin is multifaceted being discovered only in 1999, is still unveiling its function within human biology. 

A sustainable and personalized nutrition plan, will help maintain healthy ghrelin levels, and avoid yo-yo dieting, that can cause negative functions in weight, and imbalances in hormonal levels.  

Need Help With Optimizing Your Diet And Nutrition Plan To Finally Get The Results You've Been Waiting For?

The Swole Kitchen is an exclusive membership opportunity for those who are looking to pursue a performance-driven lifestyle. By combining wellness consulting, nutritional lifestyle improvement, and 1:1 customized nutrition plans to our members, our programs aim to optimize human potential. In each of our programs, you’ll receive guidance to reclaim your health, fuel your lifestyle, and pursue performance ambitions, all while learning how to make nutritional decisions from a place of self-trust and intuition. All of our coaches are committed to providing the highest level of results-driven wellness to our members.

We believe that everyone can optimize not only their athletic performance but their human potential. The way we believe we can optimize performance is through transparency, clinically effective doses, and clinically proven ingredients with evidence-based outcomes. We provide the nutrients you need to power your active lifestyle.

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