Published online by Cambridge University Press: 09 March 2007
1. Assessments were made of the energy expenditure and food intake of five boys and four girls aged between 16 and 20 years.
2. The subjects recorded their activity over a 7-day period and weighed and recorded their food intake over the same period. The energy expended by them in performing specific activities, such as sitting, standing and walking, was measured by indirect calorimetry. The total daily energy expenditure of each subject was then counted. (Values were selected from the litera ture for the energy cost of the activities which we did not measure.)
3. The following range of values was obtained for the energy cost per min of various activities: sitting, 1.0–1.8 kcal, standing, 1.2–2.0 kcal; walking, 2.0–7.5 kcal; office work 1.1–1.9 kcal; laboratory work 1.4–2.3 kcal; playing table tennis, 4.6 kcal; riding a bicycle, 3.6–6.0 kcal; running, 5.2–7.5 kcal.
4. The means and standard deviations for daily energy expenditure and for calorie intake, respectively, expressed in kcal, of the individual subjects were: for the boys 2677±184 and 3348±668, 2285±91 and 2652±418, 2730±263 and 2985±625, 2638±338 and 2379±204, 2594±244 and 3150±692; for the girls 1939±234 and 2340±524, 2261±175 and 2064±376, 2131±148 and 2011±389, 2104±171 and 2454±469.
5. There was no correlation between the daily energy expenditure and calorie intake of any subject, nor was there any relation between the weight of individual subjects and either their total energy expenditure or calorie intake.
6. It is concluded that more precise methods of measuring the energy expenditure and calorie intake of individual subjects would need to be used in order to determine if there is any correlation between these two variables over short periods.
7. The results of this study tend to confirm the findings of other workers that calorie balance is only achieved over periods longer than 7 days.