Research

Energy balance

Physical activity level (PAL) in humans is biologically constrained, with a maximum sustainable value of approximately 2.0-2.5, meaning energy intake, not just activity, drives obesity trends.

You cannot simply 'out-exercise' a poor diet because your body has a hard limit on how much energy you can burn through daily activity (max PAL ~2.5). Since energy expenditure doesn't scale infinitely with activity, managing energy intake is the critical lever for body mass regulation.

GoodQualifiesHIGH confidence
The maximum value of 2.0–2.5 is determined by energy intake... Higher values are difficult to maintain over a long period of time and generally result in mass loss, unless energy intake is supplemented.
Klaas R. Westerterp · European Journal of Applied Physiology · 2017

Why this rating

Based on compiled DLW data from multiple studies showing a narrow range of PAL despite wide variation in subject characteristics.

Source

Doubly labelled water assessment of energy expenditure: principle, practice, and promise

Klaas R. Westerterp · European Journal of Applied Physiology · 2017

DOI 10.1007/s00421-017-3641-x

narrative_reviewCited 202×
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DOI resolved against Crossref · corpus check 2026-06-10

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