Effects of concurrent training on fat mass and its distribution in individuals with overweight or obesity: a systematic review, meta-analysis, and exploratory regression analysis.

BACKGROUND: Obesity is a major global health challenge. While aerobic and resistance exercises are commonly used for obesity management, the effects of concurrent training (CT, combining both modalities) on fat mass and its distribution in individuals with overweight or obesity remain unclear. This study examined the effects of CT’s on visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and tried to identify optimal exercise prescriptions. METHODS: Six databases were systematically searched through September 2025. Randomized controlled trials comparing CT interventions with sedentary or usual-care controls in individuals with overweight or obesity were included. Meta-analyses calculated standardized mean differences (SMD) for VAT and SAT reduction. The percentage ratio of visceral/subcutaneous fat loss (%ΔV/%ΔS) was calculated, and predictors were explored through regression analysis. RESULTS: Eighteen studies were included. CT significantly reduced VAT (SMD = -0.36, 95% CI: -0.59 to -0.13, P < 0.01, I2 = 57%) and SAT (SMD = -0.26, 95% CI: -0.40 to -0.12, P < 0.01, I2 = 1%), with greater percentage reduction in VAT than SAT (%ΔV/%ΔS = 1.96 ± 1.18). Optimal effects were observed with ≥ 3 sessions per week, ≥ 60 min per session, > 180 min per week, > 15 weeks, and vigorous-intensity aerobic exercise combined with moderate-to-low-intensity resistance training. Intervention frequency and baseline VAT/SAT ratio significantly predicted fat distribution changes. CONCLUSIONS: Current evidence suggests that CT can effectively reduce fat mass and may preferentially decrease VAT compared to a sedentary lifestyle in individuals with overweight or obesity. Our findings support CT as a promising and scalable strategy for population-level obesity management, particularly for high-risk groups such as postmenopausal women and older adults. Furthermore, the identified exercise prescription parameters provide practical guidance for populations aiming to reduce adipose tissue. TRIAL REGISTRATION: CRD42024595992.