The role of physical activity and diet on overall and central obesity incidence.

OBJECTIVE Evaluate the role of different types of physical activity (PA) and diet on overall and central obesity incidence. METHODS A cohort study with 1621 adults was conducted in an urban Portuguese population. Anthropometrics were objectively obtained during 1999-2003 and 2005-2008. Overall, obesity was defined by a body mass index (BMI) ≥ 30.0 kg/m2 and central obesity by a waist circumference (WC) > 88.0 cm in women and >102.0 cm in men. Usual PA and dietary intake were assessed using validated questionnaires. Analyses of obesity incidence were conducted through different types of PA and a "healthy" dietary score. RESULTS Significant inverse associations were found between leisure-time PA and obesity incidence, namely among subjects classified into the last tertile of energy expenditure, who had approximately a 40% lower risk of developing the disease. Despite higher energy intakes, individuals with a high Physical Activity Level (PAL > 1.60) were significantly protected against obesity incidence, relative risks (RR) = 0.25 (0.09-0.72) and RR = 0.47(0.27-0.94), for overall and central obesity, respectively. No significant associations were found between dietary score and obesity incidence rates. CONCLUSIONS In our population, leisure-time PA played a significant role in preventing obesity. In both overall and central obesity, PAL above 60% of the resting metabolic rate and moderate energy intake seem to strike the right balance to prevent obesity.