Causes of Increased Energy Intake Among Children in the U.S., 1977–2010

Abstract

Changes in total energy intake have been reported among children and adolescents, but the extent to which the components of total energy-energy density; portion size; and the number of eating/drinking occasions (EO)-drive these changes is unknown. The objective of the current study was to examine the relative contribution to changes in daily total energy. Using cross-sectional nationally representative data from the Nationwide Food Consumption Survey (1977-1978); the Continuing Survey of Food Intake of Individuals (1989-1991); and the National Health and Nutrition Examination Surveys (1994-1998 and 2005-2010) for children and adolescents (aged 2-18 years), changes in total energy (kcal/day) were mathematically decomposed to determine the relative contributions of its three component parts: portion size (g/EO); energy density (kcal/g/EO); and eating/drinking occasions (n). Analyses were completed in 2012. Over the full period, there was an increase in total energy intake (+108 kcal/day) and the number of daily eating/drinking occasions (+1.2). The average portion size per eating/drinking occasion increased between 1977-1978 and 1989-1991, and then dropped by about 85 g/EO between 1989-1991 and 2005-2010. The average energy density per eating/drinking occasion has fluctuated over time, reaching its highest level in 2005-2010 (1.24 kcal/g/EO). The decomposition results show that between 1977-1978 and 2005-2010, changes in the number of eating/drinking occasions per day and portion size per eating occasion were the largest contributors to annualized changes in daily total energy (+19 and -13 kcal/day/year, respectively). Variations in trends were observed for race/ethnicity and parental education subgroups. These findings highlight potentially important intervention targets for reducing energy imbalances in U.S. youth.