Combined Effects of Gallic Acid Supplementation and Physical Training on Body Composition and Biochemical Parameters in Obese Patients: A Randomized, Double-Blinded, Placebo-Controlled Clinical Trial

<b>Background/Objectives:</b> Obesity has been linked to cardiometabolic alterations and deteriorated body composition. Gallic acid, a polyphenol with antioxidant properties, may influence these parameters; however, there is limited clinical data. The aim of this study was to evaluate the effects of gallic acid supplementation combined with physical exercise in obese individuals. <b>Methods:</b> A randomized, double-blind, placebo-controlled clinical trial with 150 participants recruited and divided into eight groups according to nutritional status (eutrophic or obese), supplementation (gallic acid 200 mg/day vs. placebo), and physical exercise (trained vs. untrained) for 12 weeks. Body composition, anthropometry, and serum biomarkers were assessed before and after the intervention. Data were analyzed using repeated-measures ANOVA. <b>Results:</b> A total of 107 participants completed the final assessment. A reduction in waist-to-hip ratio was observed in the obese group trained and supplemented with gallic acid (supplement × time interaction: <i>p</i> = 0.031). There was a reduction in waist circumference (supplement × physical exercise × time interaction: <i>p</i> = 0.041) and a reduction in skinfold thickness at the pectoral (<i>p</i> = 0.044) and abdominal (<i>p</i> = 0.036) sites. Fat-free mass showed a tendency to increase in the supplemented trained obese group (<i>p</i> = 0.054). In biochemical markers, an increase in albumin was identified in the supplement × time interaction (<i>p</i> = 0.043), especially in the trained obese group. <b>Conclusions:</b> The combination of gallic acid and physical exercise promoted improvements in abdominal adiposity and body composition markers, with favorable biochemical effects.