The Effect of Exercise Level on Weight Maintenance and Cardiometabolic Risk Factors after Clinically Significant Weight Loss

Introduction: High physical activity levels are critical for weight maintenance after clinically significant weight loss (CWL). Few studies have evaluated the effect of exercise level on weight and risk factors after CWL. Methods: Adults (body mass index (BMI): 25.0–39.9 kg/m 2 ) ( N = 39) achieved CWL (≥7%) in a 10-week OPTIFAST ® weight loss program. Participants were then randomized to aerobic exercise at the minimum physical activity recommendations (PA-REC, ~550 Metabolic Equivalent of Task (MET) minutes/week) or weight maintenance recommendations (WM-REC, ~970 MET minutes/week) for 18 additional weeks. Weight, body composition, fitness, blood pressure, and other risk factors (glucose, insulin, and lipids) were measured at baseline, after CWL (Week 10), and at follow-up (Week 28). Results: Thirty-three participants achieved CWL (~85%). Due to the COVID-19 pandemic, complete data were available for a subset of the participants who achieved CWL (PA-REC: 12, WM-REC: 9). Larger increases in estimated METs (1.7 vs 0 METs, P = 0.01) and relative (2.3 vs 0.5 mL/kg/min, P = 0.04) were observed in the WM-REC compared to the PA-REC group. Changes in waist circumference, visceral fat, and absolute approached significance between the WM-REC and the PA-REC group. No group differences were observed for weight or other risk factors ( P > 0.05). Discussion: Aerobic exercise at the weight maintenance guidelines did not result in larger improvements in weight or major traditional cardiometabolic risk factors compared with the minimum public health recommendations. After CWL, aerobic exercise at WM-REC guidelines has benefits for fitness (as measured by estimated METs) and has promise for improving central adiposity compared with the minimum PA-REC.