Energy density of foods, but not beverages, is positively associated with body mass index in adult women

BACKGROUND/OBJECTIVES: Energy density (kJ/g) may have a strong influence on energy balance. Although beverages are a considerable source of energy in the US diet, rarely have studies among free-living populations investigated the energy density of foods (EDF) and the energy density of beverages (EDB) simultaneously. We examined the independent simultaneous associations of EDF and EDB on energy intake and Body Mass Index (BMI) in adult women. SUBJECTS/METHODS: This cross-sectional design focused on 348 elementary school employees randomly selected at baseline of a worksite wellness trial in southeastern Louisiana. Two 24-hour recalls were collected, and measured heights and weights were converted into BMI (kg/m(2)). RESULTS: Those in the highest EDF tertile consumed more energy and had higher BMIs than those in the lowest tertile (P<0.05). Employees in the highest EDB tertile consumed more energy than those in the lowest, yet there was no difference in BMIs between the two groups. Multivariate regression, with controls for demographic and health variables, confirmed the positive association between EDF and BMI; a 1 kJ/g increase in EDF was associated with a 0.39 kg/m(2) increase in BMI (P=0.038). Models that did not control for EDB gave estimates of EDF that were 8% to 10% lower. CONCLUSIONS: These findings suggest that EDF and EDB play important, yet distinct, roles in energy intake and BMI. Future studies should evaluate both types of energy density as independent predictors since our results suggest that EDB can confound the association of EDF with BMI.