Can Probiotics Influence Adaptive Thermogenesis Induced by Continuous Energy Restriction after a 12-Week Intervention in Adult Males Living with Obesity? A Secondary Analysis of a Randomized Clinical Trial (São Paulo Clinical Study of Obesity and Intestinal Microbiota).

Abstract

Background: Adaptive thermogenesis represents a metabolic adaptation that reduces energy expenditure beyond what is expected from changes in fat-free mass (FFM) and fat mass (FM) following continuous energy restriction (CER). This phenomenon may impair long-term weight loss maintenance. Emerging evidence suggests that modulation of the gut microbiota may influence energy metabolism, yet the impact of probiotic supplementation on adaptive thermogenesis in humans remains unclear.

Objectives: This study aimed to investigate whether probiotic supplementation could attenuate adaptive thermogenesis induced by CER in adult males with obesity over a 12-wk intervention.

Methods: In this double-blind, placebo-controlled randomized clinical trial, adult males (body mass index: 30.0-39.9 kg/m²) were randomly assigned to receive either CER combined with probiotics (CERPRO), or CER combined with placebo (CERPLA) for 12 wk. The CER was set at 30% below total daily energy expenditure, which was calculated based on resting energy expenditure measured (REE_m) via indirect calorimetry multiplied by a physical activity factor (1.5) and adjusted for the thermic effect of food (10%). Adaptive thermogenesis was calculated as the difference between REE_m and predicted REE, adjusting for body composition changes.

Results: Forty-nine males participantes were randomized (n = 25 CERPLA; n = 24 CERPRO). Both groups experienced reductions in body weight, FM, and REE_m over 12 wk (P < 0.001), with no differences between groups (P > 0.05). Adaptive thermogenesis was present in both CERPRO (-129 ± 169 kcal) and CERPLA (-127 ± 165 kcal) groups, with no differences between groups (P = 0.966). No additive effect of probiotic supplementation was observed on REE_m, adaptive thermogenesis, FM, or FFM.

Conclusions: Probiotic supplementation did not attenuate CER-induced adaptive thermogenesis in males with obesity. Despite substantial reductions in REE_m and FM, the presence of adaptive thermogenesis persisted regardless of probiotic use. These findings suggest that probiotics do not modify metabolic adaptations associated with CER in humans.