Effects Of Weight Loss And Weight Maintenance On Inflammation In Overweight And Obese Adults

PURPOSE: Systemic inflammation, often elevated with obesity, is an independent predictor of cardiovascular disease. While weight loss reduces inflammation, little data exists on the effects of exercise during weight maintenance on inflammatory markers. The purpose of this study was to evaluate the effect of clinically significant weight loss (CWL) and weight maintenance at two different exercise levels on inflammation. METHODS: Thirty overweight and obese adults (Age: 46.1[10.7] yrs; BMI 34.2[3.5] kg/m2) participated in a 10-week weight loss intervention where they followed a hypocaloric diet and performed supervised aerobic exercise training (2-3x/week). A subset of participants that achieved CWL (≥7%) were randomized to either the minimum physical activity recommendations (PA-REC [n = 8], 550 MET min/week) or weight maintenance recommendations (WM-REC, 970 MET min/week [n = 5]) for 18 additional weeks. C-reactive protein (CRP), GlycA, weight, body composition, and fitness (maximal oxygen consumption) were evaluated at baseline, after weight loss (10 weeks), and after weight maintenance (28 weeks). RESULTS: Following weight loss, participants reduced body weight (-8.5 kg), waist circumference (-7.9 cm) (all ps < 0.001), and GlycA (-17.9 μmol/L p = 0.002), but not CRP (-0.3 mg/L, p = 0.41). Changes in CRP were associated with changes in waist circumference (r = 0.39, p = 0.04) and LDL-C (r = 0.38, p = 0.04). After weight maintenance (weeks 11-28), there was a reduction in CRP (-0.5 mg/L, p = 0.03) but not GlycA (p = 0.55). Group differences for changes in GlycA approached significance (WM-REC: -15.0; PA-REC: 3.4 μmol/L, p = 0.09). Across the entire intervention, changes in CRP were associated with changes in waist circumference (r = 0.67, p = 0.02) and fat mass (r = 0.62, p = 0.03), while changes in GlycA were associated with change in fitness assessed via estimated METs (r = -0.65, p = 0.03) from a maximal exercise test. CONCLUSIONS: Reductions in systemic inflammation were observed following a weight loss and weight maintenance intervention, which may be associated with reductions of body fat and increases in fitness. However, higher exercise levels after CWL were not associated with larger improvements in inflammation markers during weight maintenance.