Research

Hormonal

Adaptive thermogenesis is associated with significant hormonal changes, specifically decreased leptin and T3, and reduced resting heart rate.

Low leptin and T3 levels are expected during a cut and contribute to metabolic slowdown. This is a normal hormonal response to energy deficit.

GoodSupportsHIGH confidence
Absolute leptin levels decreased in both sexes (p<0.001)... These changes occurred with similar decreases in T3 (p<0.001) and resting heart rate (p<0.01) in both sexes.
Ville Isola et al. · Applied Physiology Nutrition and Metabolism · 2023

Why this rating

Clear hormonal measurements and statistical significance.

Source

Weight loss induces changes in adaptive thermogenesis in female and male physique athletes

Ville Isola et al. · Applied Physiology Nutrition and Metabolism · 2023

DOI 10.1139/apnm-2022-0372

cohort · n=48Cited 21×
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 →