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/m(2) 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.