Initial Weight Change and Long-Term Changes in Weight and Compensation during Supervised Exercise Training.

INTRODUCTION Our primary aim was to investigate the association between initial weight change and longer-term changes in weight and compensation (predicted weight loss - observed weight loss) during exercise. As secondary aims, we investigated if initial weight change was related to change in cardiometabolic risk markers and energy balance modulators. METHODS Two 6-month randomized controlled exercise trials conducted in individuals with overweight or obesity were analyzed (Study one: N=312; Study two: N=102). In both studies, participants in an exercise condition (4 kcals·kg-1·week-1 [KKW], 8 KKW, 12 KKW, or 20 KKW) were split into tertiles based on percent weight change from baseline to week 4. Tertiles 1 and 3 exhibited the least and most initial weight loss, respectively. Changes in endpoints were compared between tertiles. RESULTS At month 6, weight loss was lower in tertile 1 than tertile 3 (Study one: -3.6%, 95% CI -4.6 to -2.6; Study two: -1.8%, 95% CI -3.1 to -0.4; P≤0.034). Tertile 1 also showed greater compensation than tertile 3 in studies one (3.0 kg, 95% CI 2.2 to 3.9) and two (1.5 kg, 95% CI 0.3 to 2.6; P≤0.048). Changes in triglycerides and, in study one, high-density lipoprotein cholesterol were less favorable in tertile 1 versus tertile 3 (P≤0.043); however, changes in other cardiometabolic markers were similar (P≥0.209). In study two, tertile 1 increased energy intake and exhibited maladaptive changes in eating behaviors relative to tertile 3 (P≤0.041). No between-tertile differences in cumulative exercise energy expenditure and physical activity were evident (P≥0.321). CONCLUSIONS Less initial weight loss was associated with longer-term attenuated weight loss and greater compensation during aerobic exercise training. Individuals who display less initial weight loss during exercise may require early interventions to decrease compensation and facilitate weight loss.