Exercise Training at Maximal Fat Oxidation Intensity for Body Composition and Cardiometabolic Health in People With Overweight and Obesity: A Systematic Review With Meta‐Analysis Focusing on Prescription Dosage and Potential Moderators

ABSTRACT While exercise training at maximal fat oxidation intensity (FAT max ) is recognized as an effective strategy for improving body composition in people with overweight or obesity, its efficacy regarding cardiometabolic health and optimal prescription warrants systematic evaluation. We conducted a PRISMA‐conform systematic review and meta‐analysis (PROSPERO: CRD420251036468), reviewing literature from PubMed, Cochrane Library, Embase, SPORTDiscus, and Web of Science through December 6, 2025. A three‐level random‐effects model with restricted maximum likelihood (REML) was applied. Study quality was assessed with the TESTEX scale and Cochrane RoB 2.0, and certainty with GRADE. Nineteen randomized trials ( N = 644; overweight/obesity) were included, with overall moderate methodological quality. Compared with controls, exercise training at FAT max reduced body weight (−3.66 kg, p < 0.01), BMI (−1.66 kg/m 2 , p < 0.01), body fat percentage (−2.32%, p < 0.01), fat mass (−2.86 kg, p < 0.01), and waist circumference (−4.21 cm, p < 0.01), and improved (SMD = 1.45, p < 0.01) while reducing fasting circulating glucose (SMD = −1.28, p < 0.01), insulin (SMD = −0.53, p < 0.01), and HOMA‐IR (SMD = −0.57, p < 0.01). Moderator analyzes indicated significant influences of age, BMI, ethnicity, and methodological design on selected outcomes. Nonlinear dose–response modeling identified an optimal total exercise volume of ~2446 min for maximal body composition benefit. Overall GRADE ratings were predominantly very low to moderate. In conclusion, exercise training at FAT max can effectively improve body composition and cardiometabolic health, but standardized assessment protocols are needed to mitigate methodological heterogeneity and refine tailored FITT‐VP exercise prescriptions.