This secondary analysis examined the influence of changes in physical activity (PA), sedentary time and energy expenditure (EE) during dietary energy restriction on the rate of weight loss (WL) and 1-year follow-up weight change in women with overweight/obesity.Measurements of body weight and composition (air-displacement plethysmography), resting metabolic rate (indirect calorimetry), total daily (TDEE) and activity EE (AEE), minutes of PA and sedentary time (PA monitor) were taken at baseline, after 2 weeks, after ≥5% WL or 12 weeks of continuous (25% daily energy deficit) or intermittent (75% daily energy deficit alternated with ad libitum day) energy restriction, and at 1-year post-WL. The rate of WL was calculated as total %WL/number of dieting weeks. Data from both groups were combined for analyses.Thirty-seven participants (age=35±10y; BMI=29.1±2.3kg/m2) completed the intervention (WL=-5.9±1.6%) and 18 returned at 1-year post-WL (weight change=+4.5±5.2%). Changes in sedentary time at 2 weeks were associated with the rate of WL during energy restriction (r=-0.38; p=0.03). Changes in total (r=0.54; p<0.01), light (r=0.43; p=0.01) and moderate-to-vigorous PA (r=0.55; p<0.01), sedentary time (r=-0.52; p<0.01), steps per day (r=0.39; p=0.02), TDEE (r=0.46; p<0.01) and AEE (r=0.51; p<0.01) during energy restriction were associated with the rate of WL. Changes in total (r=-0.50; p=0.04) and moderate-to-vigorous PA (r=-0.61; p=0.01) between post-WL and follow-up were associated with 1-year weight change (r=-0.51; p=0.04).These findings highlight that PA and sedentary time could act as modifiable behavioural targets to promote better weight outcomes during dietary energy restriction and/or weight maintenance.
Keywords: Physical activity; energy expenditure; sedentary time; weight loss; weight regain.