Energy intake and physical fitness in children and adults of both sexes

Submaximal power output and body fatness have been measured in 1307 subjects recruited from 375 families coming from an area of 80 km around Quebec city. Total energy, carbohydrate, sugar, fat, saturated fat and alcohol intakes were calculated from a 3-day dietary record. The association between dietary intakes and the indicators of physical fitness was studied in adults (n=727) and children (n=580) of both sexes. Correlation analyses with residuals of age performed in each generation and sex subsample showed that body fatness is significantly but negatively associated with all intakes (−0.16≤r≤−0.50), with the exception of alcohol intake. On the other hand, multiple correlations of all intakes on submaximal power output range from 0.26 to 0.30 in adults, and from 0.20 to 0.24 in children. These observations suggest that submaximal power output is less related to energy intakes and that the association tends to be slightly more important in adults than in children. These data support the contention that physical fitness is determined by the genotype and the habitual energy expenditure and to a lesser degree by the nutritional habits.