Relative fat oxidation is higher in children than adults

Abstract:

Prepubescent children may oxidize fatty acids more readily than adults. Therefore, dietary fat needs would be higher for children compared with adults. The dietary fat recommendations are higher for children 4 to 18 yrs (i.e., 25 to 35% of energy) compared with adults (i.e., 20 to 35% of energy). Despite this, many parents and children restrict dietary fat for health reasons.

METHODS: This study assessed whether rates of fat oxidation are similar between prepubescent children and adults. Ten children (8.71.4yr, 3313 kg meanSD) in Tanner stage 1 and 10 adults (41.68 yr, 74 13 kg) were fed a weight maintenance diet for three days to maintain body weight and to establish a consistent background for metabolic rate measurements (all foods provided). Metabolic rate was measured on three separate occasions before and immediately after breakfast and for 9 hrs using a hood system (twice) or a room calorimeter where continuous metabolic measurements were taken.

RESULTS: During all three sessions whole body fat oxidation was higher in children (lower RQ) compared to adults (mean RQ= 0.84 .016 for children and 0.87.02, for adults, p<0.02). Although, total grams of fat oxidized was similar in children (62.7 20 g /24 hrs) compared to adults (51.4 19 g /24 hrs), the grams of fat oxidized relative to calorie expenditure was higher in children (0.047 .01 g/kcal, compared to adults (0.032 .01 p<0.02). Females oxidized more fat relative to calorie expenditure than males of a similar age. A factor way ANOVA showed no interaction between gender and age in terms of fax oxidation.

CONCLUSIONS: These data suggest that fat oxidation relative to total calorie expenditure is higher in prepubescent children than in adults. Consistent with current dietary guidelines, a moderate fat diet is appropriate for children within the context of a diet that meets their energy and nutrient needs.