Research

Hormonal

Chronic aerobic exercise induces a significant increase in fasting plasma ghrelin levels proportional to the magnitude of weight loss, independent of changes in caloric intake.

If you start an aerobic exercise program and lose weight, your body will naturally increase hunger hormones (ghrelin) to try to regain the weight. This happens even if you don't change your diet. Expect to feel hungrier as you lose weight; this is a normal biological signal, not a sign that your exercise routine is failing.

GoodSupportsHIGH confidence
Exercise-induced weight loss was associated with a progressive increase in plasma ghrelin levels over baseline, achieving statistical significance at 12 months... Ghrelin levels increased commensurately with the amount of weight lost... There was no change in caloric intake in either group and no effect on ghrelin of exercise per se independent of its impact on body weight.
Karen E. Foster‐Schubert et al. · The Journal of Clinical Endocrinology & Metabolism · 2005

Why this rating

Randomized controlled trial with a large sample size (n=173) and long duration (12 months), though self-reported diet introduces minor measurement error.

Source

Human Plasma Ghrelin Levels Increase during a One-Year Exercise Program

Karen E. Foster‐Schubert et al. · The Journal of Clinical Endocrinology & Metabolism · 2005

DOI 10.1210/jc.2004-2081

rct · n=173Cited 191×
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DOI resolved against Crossref · corpus check 2026-06-10

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