Caloric intake and expenditure of obese boys.

Caloric intake and expenditure of children in four families were assessed by nonparticipant observations of family dinners and school lunches. In each family there were one obese boy and one nonobese brother whose ages were within two years of each other. For family dinners the nonobese brother served as a control; for school lunches, a nonobese peer served as a control. The obese boys consumed more calories (766 +/- 290) than did their nonobese brothers at dinner (504 +/- 183) and far more (907 +/- 217) than their nonobese peers at lunch (500 +/- 386). The obese boys also ate faster (65.7 +/- 37.0 kcal/minute) than their brothers at dinner (31.7 +/- 13.8 kcal/minute) and far faster (103.5 +/- 40.9 kcal/minute) than their nonobese peers at lunch (46.2 +/- 22.5 kcal/minute). Time-sampled activity assessments showed the obese boys far less active than their controls inside the home, slightly less active outside the home, and equally active at school. When these activity values were converted into energy expenditure by measurement of oxygen consumption, obese boys expended more calories in moving than did their controls; as a result, there was no difference in energy expenditure between obese and nonobese boys at home and greater energy expenditure outside the home and at school. Increased intake, thus, and not decreased caloric output maintained the obesity of these four boys. In this respect, obesity in childhood may differ from obesity in adult life.