Research

Energy balance

Metabolic adaptation during weight loss involves a 15-20% reduction in daily energy expenditure beyond what is expected from mass loss, which persists until the previous weight is regained.

When you lose weight through dieting, your body burns 15-20% fewer calories than expected for your new size. This 'metabolic adaptation' does not go away over time; it stays until you regain the weight. This is why maintaining weight loss through diet alone is so difficult—you must eat significantly less than a healthy person of your new weight would.

GoodSupportsHIGH confidence
For those with obesity participating in a low-calorie diet-induced weight loss program, studies dating back 40 years have shown an approximately 15%–20% reduction in daily energy expenditure that is in addition to the reduction expected from lower lean and fat mass energy needs... Long-term follow-up of such low-calorie diet-induced weight loss studies shows that this energetic (metabolic) adaptation response remains intact and does not 'adjust' to the new lower adipose mass over time [17, 19].
Jonathan Q. Purnell et al. · Journal of Internal Medicine · 2025

Why this rating

Cites multiple long-term studies.

Source

Metabolic and appetitive regulation of adipocyte mass during treatment of obesity

Jonathan Q. Purnell et al. · Journal of Internal Medicine · 2025

DOI 10.1111/joim.70045

narrative_reviewCited 3×
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DOI resolved against Crossref · corpus check 2026-06-10

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