The impact of maximal fat oxidation intensity exercise on glucose and lipid metabolism in individuals with overweight or obesity: A systematic review and meta-analysis

This study provides the first quantitative synthesis evaluating the chronic effects of FATmax training on glucose and lipid metabolism in individuals with overweight or obesity, while systematically exploring the moderating roles of participant characteristics and intervention protocols. A comprehensive search of seven databases (e.g., PubMed, Web of Science) was conducted up to August 2025, identifying 24 controlled trials involving 638 participants. Random-effects meta-analyses showed that FATmax training produced significant improvements in multiple glycolipid metabolic markers. Specifically, large standardized reductions were observed in fasting plasma glucose (Hedges’ g = -1.05), insulin resistance (Hedges’ g = -0.82), and fasting insulin (Hedges’ g = -0.75), alongside moderate improvements in triglycerides (Hedges’ g = -0.55), total cholesterol (Hedges’ g = -0.23), and high-density lipoprotein cholesterol (HDL-C; Hedges’ g = 0.51). Notably, the large standardized effects on glycemic markers suggest potentially clinically meaningful improvements in glycemic control. Subgroup analyses indicated that HDL-C adaptations were significantly enhanced in male participants, weight-bearing modalities, and protocols incorporating warm-up sessions or concurrent dietary restriction (p < 0.05). Furthermore, meta-regression identified baseline HDL-C (β= -2.955), exercise intensity (β = 0.053), and session duration (β = 0.058) as significant predictors of HDL-C improvement. Crucially, we derive the first clinically actionable, personalized thresholds from interaction analyses: for individuals with low baseline HDL-C (≤ 1.36 mmol/L), efficacy is maximized when session duration exceeds 60 minutes (Hedges’ g = 1.19) or intensity surpasses 42.2% V ̇ O2max (Hedges’ g = 1.10); whereas for those with higher baseline levels, extending duration (≥ 60 min) is the primary requisite for significant benefits (Hedges’ g = 0.61). In conclusion, FATmax training produces significant and potentially clinically meaningful improvements in glucose and lipid metabolism in individuals with overweight or obesity. These effects are modulated by individual characteristics and intervention parameters. Future research should prioritize standardized FATmax determination protocols and diverse populations to validate these personalized prescription parameters.