The pattern of food intake can affect the regulation of body weight and lipogenesis. We studied the effect of meal frequency on human energy expenditure (EE) and its components. During 1 week ten male adults (age 25-61 years, body mass index 20.7-30.4 kg/m2) were fed to energy balance at two meals/d (gorging pattern) and during another week at seven meals/d (nibbling pattern). For the first 6 d of each week the food was provided at home, followed by a 36 h stay in a respiration chamber. O2 consumption and CO2 production (and hence EE) were calculated over 24 h. EE in free-living conditions was measured over the 2 weeks with doubly-labelled water (average daily metabolic rate, ADMR). The three major components of ADMR are basal metabolic rate (BMR), diet-induced thermogenesis (DIT) and EE for physical activity (ACT). There was no significant effect of meal frequency on 24 h EE or ADMR. Furthermore, BMR and ACT did not differ between the two patterns. DIT was significantly elevated in the gorging pattern, but this effect was neutralized by correction for the relevant time interval. With the method used for determination of DIT no significant effect of meal frequency on the contribution of DIT to ADMR could be demonstrated.