Resting metabolic rate (RMR) and respiratory exchange ratio (RER) were measured, using indirect calorimetry, in 9 healthy, male subjects (28.6 ± 3.3 years) under three conditions: (1) an inpatient, meal-controlled protocol (IPM) in which subjects were fed an evening meal and slept overnight in the laboratory prior to the morning test; (2) an outpatient, meal-controlled protocol (OPM) in which subjects were fed the same meal but slept at home prior to being transported to the laboratory for testing, and (3) and outpatient protocol (OP) in which meal was not controlled, but subjects were instructed to fast for 12 h prior to testing. There were no statistically significant differences in RMR between protocols (IPM = 7,928 ± 360, OPM = 8,015 ± 331 and OP = 7,987 ± 315 kJ/day) or in fasting RER (IPM = 0.82 ± 0.01, OPM = 0.82 ± 0.02 and OP = 0.81 ± 0.02). These data indicate that in young, healthy males RMR and RER are similar when measured under inpatient or outpatient conditions.