The influence of physical activity-induced energy expenditure on the variance in body weight change among individuals during a diet intervention

SummaryObjectiveWe investigated the relationship between the variability in body weight change among individuals and diet restriction or physical activity during a 14-week intervention.DesignA prospective clinical trial with a 14-week weight reduction intervention design. In total, 90 middle aged, Japanese, obese women enrolled as subjects.MeasurementsThe outcome variable was the change in body weight during the intervention period. Other primary variables were total energy intake, carbohydrate intake, fat intake, protein intake, total energy expenditure (TEE), and activity energy expenditure (AEE). Diet intake was assessed by 3 days, weighed dietary records and dietary recall interviews. Physical activity was assessed by a uniaxial accelerometry sensor and a diary of exercise.ResultsSignificant reductions were observed in body weight (−8.5 kg) as a result of intervention. When the subjects were assigned to three categories depending on AEE during intervention, the loss of body weight was significantly greater for subjects within the upper (−9.6 kg) AEE category than for those in the middle (−8.5 kg) or lower AEE (−7.5 kg) categories. In addition, a significant correlation (r = 0.57, p < 0.0001) was observed between a subject's AEE before and during the intervention. On the other hand, no significant correlation was observed between body weight reduction and energy intake, indicating that strict diet restriction does not always result in a large weight loss.ConclusionActivity energy expenditure, not only through voluntary exercise but also through spontaneous, daily, physical activities can have a positive effect on reducing body weight.