Are basal metabolic rate prediction equations appropriate for overweight and obese adolescents?

The known predictive equations can present different values for basal metabolic rate (BMR) compared to those measured through indirect calorimetry. The objective of this study was to describe BMR through indirect calorimetry of overweight and obese boys (with ages between 12 and 17 years old) living in Porto Alegre, Brazil, and to compare the measured value with values estimated by predictive equations. Thirty-five volunteers had their BMR measured through indirect calorimetry in the morning, under standard conditions of fasting, rest and environment. The average (± standard deviation) of measured BMR was of 1,900.5 ± 248.8 kcal/24 hours. Estimated BMR were significantly greater, in three of four equations (6.5 to 9.5%), than measured BMR (p < 0.05). These results show that predictive equations are not suitable to estimate BMR in these groups of overweight and obese boys. The use of estimated BMR can lead, in most cases, to an overestimation of energy requirements for boys with similar characteristics.