Obesity has been increasing in Brazil in the last two decades, but there are no recent population data on dietary intake and physical activity, the two major components of body weight gain. The association of food intake (calorie and fat) and energy expenditure with body mass index (BMI) was studied in 91 university employers. Food intake was estimated by the means of four 24-hour recalls and by a semi-quantitative food frequency questionnaire developed using the most frequent consumed Brazilian foods. Weight and height were measured and the body mass index was calculated by dividing the weight in kg by the height in m². Physical activities developed in the previous month were estimated through a questionnaire that included activities developed at work, in the spare time and when commuting to work or school. Energy expenditure estimation was based on the WHO equations. Multivariate linear analysis having BMI as the dependent variable showed positive associations with age (p=0.02), occupation (support staff being heavier than professors, p=0.004), sex (females were heavier than males, p=0.04). Furthermore, the daily increase of 500 calories in the energy expenditure was associated to a weight reduction of approximately 2kg in an individual with a height of 1.60 m (p=0.008). For both methods used to estimate the food intake (24-hour recall and food frequency questionnaire), energy intake and fat intake were associated to BMI (p< 0.05), but sex modified these associations. For women there was a negative association between fat and energy intake and BMI, whereas for men this association was positive but irrelevant. This study indicated an increased risk of obesity with age, and an increased risk for staff employers and females. A possible misclassification of food intake among obese female was also suggested.
obesity; body mass index; food consumption; cross-sectional studies; food habits; physical activity
