Research

Energy balance

Spontaneous Physical Activity (SPA) measured in a respiratory chamber does not significantly decrease in response to calorie restriction in non-obese individuals, whereas free-living Physical Activity Level (PAL) decreases.

When you diet, your body reduces your free-living activity (PAL), such as fidgeting or general movement, even if your structured exercise remains constant. This unconscious reduction contributes to weight loss resistance. To counteract this, you may need to incorporate structured exercise to maintain total energy expenditure.

GoodQualifiesHIGH confidence
Neither measure of SPA decreased significantly in any group. PAL decreased at Month 3 in the CR and LCD groups, but not in the CR+EX group, who engaged in structured exercise.
Corby K. Martin et al. · Obesity · 2007

Why this rating

Robust measurement of both chamber SPA and free-living PAL using doubly labeled water and respiratory chambers.

Source

Effect of Calorie Restriction on Resting Metabolic Rate and Spontaneous Physical Activity

Corby K. Martin et al. · Obesity · 2007

DOI 10.1038/oby.2007.354

rct · n=48Cited 235×
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DOI resolved against Crossref · corpus check 2026-06-10

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