Ghrelin

Ghrelin is a hormone primarily produced by the stomach lining, known as the hunger hormone. It rises before habitual meal times and drops after eating. Ghrelin doesn't just increase the sensation of hunger; it also enhances the appeal of food's aroma and taste and activates the brain's reward centers - which is why food smells and tastes better when you're hungry.

For weight loss, ghrelin presents a significant challenge. With a calorie deficit and weight loss, ghrelin levels rise - in studies by as much as 24% higher than before weight loss. This increased hunger can persist for 6-12 months after weight loss, which partly explains why weight maintenance is so difficult. The body simply demands more food than before, because the hormonal signal says 'you're starving.'

Ghrelin also has a circadian rhythm: it rises particularly toward evening, which explains the prevalence of evening eating. Sleep deprivation raises ghrelin further - even one bad night significantly increases the next day's hunger.

Ghrelin can be managed with practical measures: a regular meal schedule 'teaches' ghrelin to rise at specific times, making hunger more predictable. Adequate protein and fiber lower ghrelin most effectively after a meal. Sufficient sleep (7-9 hours) keeps ghrelin in check. Stress management also helps, as cortisol raises ghrelin. A slow, moderate weight loss pace causes less ghrelin increase than an aggressive diet. Ghrelin is directly related to leptin, cortisol, and calorie deficit concepts.

Last updated: March 30, 2026