LAUSR

Abstract 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), RMR (indirect calorimetry), total daily EE (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 (aged 35 (sd 10) years; BMI = 29·1 (sd 2·3) kg/m2) completed the intervention (WL = –5·9 (sd 1·6) %) and 18 returned at 1-year post-WL (weight change=+4·5 (sd 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 d (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.