Energy metabolism in healthy black Kenyan children.

Abstract

1. Twenty-four healthy black Kenyan children, mean age 29 (SD 19) months, were studied over a 24 h period. Energy expenditure (EE) was determined using a ventilated-hood indirect calorimeter; measuring oxygen consumption and carbon dioxide production. Metabolizable energy intake was measured in twenty children. Anthropometric measurements were used to estimate surface area and lean body-weight. 2. The mean daily intake of metabolizable energy was 338.4 (SE 28.4) kJ/kg; 70% of gross dietary energy being provided by carbohydrate. The level of postprandial EE was significantly (P less than 0.05) higher than the resting level (12.6 (SE 0.47) and 11.38 (SE 0.37) kJ/kg per h respectively) while the level of the postprandial respiratory quotient (RQ) was similar to the resting level (0.94 (SE 0.02) and 0.98 (SE 0.03 respectively). In 33% of total observations of the resting RQ the value was more than 1.0. These findings suggest that short-term fat storage may be a normal feature of metabolism in children, and also that the energy cost of (postprandial) fat synthesis is increased by a high-carbohydrate diet. 3. Values for the resting metabolic rate and various estimators of body size were compared using regression analysis. It was evident that, in these young children with considerable variation in body composition, body-weight remained a satisfactory metabolic-size estimator.