The international recommendations on human energy requirements (ER), proposed by FAO/WHO/UNU in 1985, represent a significant methodological progress since they changed the method of estimating ER from the average energy intake of healthy people to the daily energy expenditure of the population. This change was based on the observation that estimation based on energy intake yielded a circular argument in which the intake was not the most appropriate way to maintain healthy weight and optimal levels of physical activity for health on the long run. The 1994 meeting of the International Dietary Energy Consultative Group, published in 1996, as well as papers by national and international authors indicate that the principal problems in the proposed method are related to: • the adequacy of the equations to estimate the basal metabolic rate (BMR); • the physical activity level (PAL) values; • the mechanisms of adaptation; • the method proposed to children under 10 years. For Brazil, the BMR equations tend to overestimate adults' BMR and the PAL values are not appropriated to the population, as shown by recent studies on BMR measurement and PAL values estimation. Comparing the ER assessed by the factorial method (based on the duration of the activities and the correspondent integrated energy indexes) with the simplified one (based on recommended PAL values), this paper shows that the recommended PAL values: • for 18-59 year-old women represent higher ER (from 11% to 17%) than necessary which could make these women become obese; • for 10-17 and 60+ year-old males and 11-17 year-old females will lead to undernutrition by not incorporating provisions for the occupational activities; • for 18-59 year-old males can only be used to calculate the mean for the total population, because its use for the rural and urban populations separately will lead to under and overnutrition, respectively. At last, the paper shows that the mean ER based on the estimated PAL values is very near to the mean ER based on the factorial method for all the strata defined. Considering that the Brazilian Official Statistical System has enough information to estimate PAL values more adequate to several stratifications of the population, this paper suggests determining ER based on the national estimated PAL values.
Energy requirements; Surveys; Energy metabolism; Estimation methods
