Effects of an 8-Week Time-Restricted Eating and Walking Exercise on Regional Fat Distribution and Lean Mass in Women with Hidden Obesity: A Randomized Controlled Trial

Objectives: Explore and compare the effects of 8-week time-restricted eating (TRE), walking exercise, and their combination on fat and lean muscle distribution in female college students with hidden obesity. Methods: A total of 68 participants were randomly assigned to four groups: Control (CON), TRE, Exercise (EXE), and TRE + EXE. An 8-week intervention was begun according to a predetermined experimental plan, comparing changes in body fat and lean tissue indices before and after the intervention. Results: Before and after the intervention, the TRE group showed a significant decrease in body mass, body mass index (BMI), and total lean mass (p < 0.05). The EXE group saw a significant reduction in visceral fat area, visceral fat mass, and visceral fat volume (p < 0.01). The TRE + EXE group experienced a significant decrease in android lean mass (p < 0.05); Comparing before and after the intervention, there were no statistically significant differences in the body fat percentage, total fat mass, fat and lean in the android and gynoid areas, and %fat in trunk/%fat in legs among the CON, TRE, EXE, and TRE + EXE groups (p > 0.05). After the intervention, there were no significant differences in the body fat percentage, total fat mass, total lean mass, fat and lean in the android and gynoid areas, %fat in trunk/%fat in legs, visceral fat area, visceral fat mass, visceral fat volume, subcutaneous fat area, subcutaneous fat mass, and subcutaneous fat volume among the four groups (p > 0.05). Conclusions: An 8-week TRE intervention in young women with hidden obesity reduced body mass and BMI but also decreased total lean mass, potentially compromising metabolic health, with no statistically significant changes in total body fat or regional fat distribution. Walking exercise showed significant reductions in visceral adiposity indicators (VFA, VFM, VFV), whereas the combined TRE + EXE group did not achieve comparable reductions. These findings suggest that while isolated TRE facilitates body mass loss, it carries a distinct risk of muscle tissue loss and may not confer comparable benefits on visceral fat reduction as walking exercise. However, the generalizability of these preliminary observations is constrained by methodological limitations including retrospective registration, participant attrition, and restricted statistical power. Consequently, these exploratory outcomes must be interpreted with caution, warranting future robust, large-scale trials with enhanced compliance monitoring to optimize prescriptive guidelines for this specific cohort.