Among 221 sedentary women with overweight (mean BMI 28.3), an 800 kcal/day diet drove BMI to 23.9, slashing predicted 10-year MACE and type 2 diabetes risk across all three arms — Diet+Aerobic, Diet+Resistance, and Diet-only. By the 1-year follow-up, BMI had rebounded to 25.8, and MACE risk partially reversed in every group. Critically, T2D risk rebounded in the aerobic and diet-only groups, but the Diet+Resistance group maintained a statistically significant net reduction (p = 0.003), with exercise adherence independently associated with lower T2D risk rebound (p = 0.024).
The finding that resistance training uniquely preserves metabolic gains after weight loss is clinically meaningful and mechanistically plausible — skeletal muscle is the primary site of insulin-mediated glucose disposal, and resistance exercise increases muscle mass and GLUT4 expression in ways aerobic exercise does not replicate equivalently. This trial adds to a growing body of evidence that the type of exercise paired with caloric restriction matters, not just the calorie deficit itself. Limitations are notable: the cohort was exclusively women aged 21–49, limiting generalizability to men and older adults. The very-low-calorie protocol (800 kcal/day) is aggressive and clinically supervised, reducing real-world applicability. The study is also observational at follow-up, so adherence effects are associative rather than causal. Still, for adults managing weight in a GLP-1 era where muscle loss is a growing concern, this trial offers a practical message: resistance training during and after weight loss may be the most durable metabolic investment.