Ghrelin
The hunger hormone — stimulates appetite before meals.
Plain English
Patient-Friendly Explanation
Ghrelin is your "hunger hormone." Levels rise before meals and fall after eating. Some weight loss methods increase ghrelin, making you hungrier — which is why medical support helps.
Medical
Clinical Definition
Ghrelin is a 28-amino acid peptide secreted primarily by gastric fundus cells. It acts on the arcuate nucleus to stimulate appetite. Levels increase during calorie restriction, contributing to weight regain.
Key Insight
Why It Matters
GLP-1 agonists suppress ghrelin secretion, providing dual appetite control. Understanding this mechanism helps patients appreciate why medication can be necessary.
What ghrelin is
Ghrelin is the 'hunger hormone'. It is produced mainly in the stomach, rises before meals, falls after you eat, and tells the brain's appetite centre that it is time to eat. It is one half of the brain's energy-balance system — the half that drives hunger.
Why dieting makes you hungrier (the biology)
This is the part that surprises most patients: hunger during a diet is not weak willpower — it is a measured hormonal response.
- When you eat less, ghrelin levels rise — the body defends its energy stores as if food were scarce
- Ghrelin stays elevated during active weight loss, which is why the first weeks are the hungriest
- The rise is larger with rapid, aggressive restriction than with a modest deficit
- As weight stabilises, ghrelin tends to settle — the hunger signal is temporary if the plan is sustainable
Sleep, stress and ghrelin
Two everyday factors amplify the hunger hormone:
- Short sleep raises ghrelin and lowers leptin — a double hit that measurably increases next-day intake
- Stress and high cortisol also increase ghrelin-driven appetite, especially for energy-dense foods
- Prioritising sleep (7+ hours) and managing stress are therefore legitimate parts of a weight-loss plan, not optional extras
How to manage ghrelin-driven hunger
You cannot switch ghrelin off, but you can work with it:
- Eat enough protein and fibre — both suppress ghrelin more effectively than fat or simple carbs
- Keep meals regular — erratic eating keeps the signal high
- Choose a modest deficit (0.5–1% of body weight per week) rather than crash dieting
- Sleep consistently — the cheapest hunger-reduction tool available
- Volume matters — bulky, low-energy-density foods (vegetables, soups) fill the stomach and blunt the signal
Common questions
What is the hunger hormone ghrelin?
Ghrelin is a hormone produced mainly by the stomach that rises before meals and signals hunger to the brain. It is part of the body's energy-balance system and is the main driver of the feeling of hunger.
Why am I hungrier now that I'm dieting?
Because eating less raises ghrelin — the body treats an energy deficit as a threat and amplifies hunger signals. This is a measured hormonal response, not a character flaw. It settles as weight stabilises and is far worse on crash diets than on modest, sustainable deficits.
Does sleep affect ghrelin?
Yes. Short sleep raises ghrelin and lowers its partner hormone leptin, which measurably increases hunger and next-day food intake. Protecting 7+ hours of sleep is one of the most effective hunger-management tools.
Can I lower ghrelin?
Not directly, and you don't need to — the goal is to work with it. Protein and fibre suppress it after meals, regular meals keep it stable, and a modest calorie deficit keeps the rise manageable. The clinic's plans are designed around exactly this biology.
Sources
Reviewed against standard medical references.
Medically reviewed by
Family Physician & Registered Acupuncturist, Accord Medical Clinic. MBBS (NUS), Graduate Diploma in Family Medicine (NUS), Graduate Diploma in Acupuncture (Singapore College of TCM).
Last reviewed: August 2026
This page is general health education, not medical advice. Whether any treatment is appropriate for you is a decision made in consultation after assessment.
