Research

Energy balance

Losing 9.0 kg (20 lb) or more improves physical function and vitality in overweight and obese women (BMI ≥30.0 kg/m2), but paradoxically decreases physical function and vitality in lean women (BMI <25.0 kg/m2).

If you are overweight, losing weight (especially 20+ pounds) can significantly improve your physical function and energy. However, if you are already lean, losing significant weight may be a sign of underlying health issues and could worsen your physical function. Focus on maintaining your weight if you are lean.

GoodQualifiesMEDIUM confidence
Weight loss in overweight women was associated with improved physical function and vitality as well as decreased bodily pain... among women in the lowest BMI category, a comparable weight loss was paradoxically associated with a 12-point decrease in physical function
Jennifer Fine · JAMA · 1999

Why this rating

Large prospective cohort, but the subgroup of lean women losing significant weight was small (n=95), and involuntary loss (illness) could not be fully ruled out.

Source

A Prospective Study of Weight Change and Health-Related Quality of Life in Women

Jennifer Fine · JAMA · 1999

DOI 10.1001/jama.282.22.2136

cohort · n=45375Cited 419×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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