Abstract
BACKGROUND: Epidemiologic evidence is sparse on the effect of dietary behaviors and diet quality on body mass index (BMI; calculated as kg/m(2)), which can be important drivers of the obesity epidemic. OBJECTIVE: This study investigated the relationships of frequency of eating and time of intake to energy density, nutrient quality, and BMI using data from the International Study on Macro/Micronutrients and Blood Pressure including 2,696 men and women aged 40 to 59 years from the United States and the United Kingdom. DESIGN: The International Study on Macro/Micronutrients and Blood Pressure is a cross-sectional investigation with four 24-hour dietary recalls and BMI measurements conducted between 1996 and 1999. Consumption of solid foods was aggregated into eating occasion. Nutrient density is expressed using the Nutrient Rich Food Index 9.3. The ratio of evening/morning energy intake was calculated; mean values of four visits were used. STATISTICAL ANALYSES PERFORMED: Characteristics across eating occasion categories are presented as adjusted mean with corresponding 95% CI. Multiple linear regression models were used to examine associations of eating occasions, ratio of evening/morning energy intake, dietary energy density, and Nutrient Rich Food Index 9.3 with BMI. RESULTS: Compared to participants with fewer than four eating occasions in 24 hours, those with six or more eating occasions in 24 hours had lower mean BMI (27.3 vs 29.0), total energy intake (2,129 vs 2,472 kcal/24 hours), dietary energy density (1.5 vs 2.1 kcal/g), and higher Nutrient Rich Food Index 9.3 (34.3 vs 28.1). In multiple regression analyses, higher evening intake relative to morning intake was directly associated with BMI; however, this did not influence the relationship between eating frequency and BMI. CONCLUSIONS: Our results suggest that a larger number of small meals may be associated with improved diet quality and lower BMI. This may have implications for behavioral approaches to controlling the obesity epidemic.