Self-reported energy intake by age in overweight and healthy-weight children in NHANES, 2001-2008.

OBJECTIVE: Variation in energy intake by weight status at different ages may explain inconsistencies in previous research on energy intake and obesity. Therefore, our objective was to determine the relationship between reported daily energy intake and categorized weight status across childhood.
METHODS: We examined dietary reports of children ages 1 to 17 years by using the National Health and Nutrition Examination Survey, 2001-2008 (N = 12648). Using measured height and weight, we categorized weight status based on weight-for-length percentile (age <2 years) or BMI percentile (ages 2-17 years) using current recommendations. Dietary intake was reported by using the repeatedly validated automated multiple pass method, a detailed 2-day 24-hour recall. We used ordinary least squares regression to examine the interactions of age and weight category on total energy intake, controlling for gender, race, ethnicity, and income.
RESULTS: Weight status and age both have positive associations with self-reported energy intake. However, the interaction between weight and age demonstrates a negative effect throughout childhood, such that young obese/overweight children reported consuming significantly more calories and obese/overweight adolescents reported consuming fewer calories than their same-age healthy-weight peers.
CONCLUSIONS: In a nationally representative cross-sectional sample, overweight and obese girls older than 7 years and boys older than 10 years reported consuming fewer daily calories than their healthy-weight peers. One explanation for this would be that increased energy intake in early childhood is related to the onset of obesity, but other mechanisms, such as differences in energy expenditure, may contribute more to maintaining obese/overweight status through adolescence.