Research

Mixed

Rapid weight loss via caloric and fluid restriction (approx. 5% body weight over 7 days) impairs physical performance, alters mood negatively, and disrupts endocrine balance in judo athletes.

If you are an athlete in a weight-class sport, avoid losing 5% of your body weight in the week before competition through severe restriction. This study shows that doing so significantly reduces your grip strength and negatively impacts your mood (increasing fatigue and tension) and hormonal balance, even if you have time to rehydrate and eat before the event. Prioritize maintaining your natural weight to preserve performance capacity.

GoodSupportsHIGH confidence
our results suggest that the combination of energy restriction and intense exercise training, which causes weight reduction before a competition, adversely affects the physiology and psychology of judo athletes and impairs physical performance before the competition.
Fabrice Degoutte et al. · International Journal of Sports Medicine · 2006

Why this rating

Randomized controlled trial with clear intervention and control groups, though sample size is small (n=20).

Source

Food Restriction, Performance, Biochemical, Psychological, and Endocrine Changes in Judo Athletes

Fabrice Degoutte et al. · International Journal of Sports Medicine · 2006

DOI 10.1055/s-2005-837505

rct · n=20Cited 249×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →