It has been shown in overfeeding studies of animals and humans that weight gain is highly variable but often small. Whilst there is an enhancement of oxygen consumption in the hours after eating, this diet-induced thermogenesis is too small to account for ability of some individuals to avoid weight gain during over feeding [1]. In 1967, Miller and colleagues reported that oxygen consumed by adult humans during a standardised exercise test was increased following a meal and that the effect was proportional with the calorie load [2]. We have reproduced and extended this study. Thirteen healthy male undergraduate students aged 20 to 23 years were recruited to the study. Oxygen consumption was measured at rest (seated) and during exercise (Human Respiratory Kit, LabChart v8, AD Instruments). Exercise consisted of stepping up and down (30cm) every 2 seconds. Measurements were taken during the last minute of five minutes of rest or exercise. Experimental interventions were fasting, carbohydrate-rich meal and a protein-rich meal. The target for each meal was 1650 kcal which is two-thirds of the recommended dietary intake. Subjects arrived following a 5 hour fast, completed both resting and exercising measurements and then returned one hour after completing their meal intervention to repeat the measurements. Three interventions were scheduled for the same time and day of consecutive weeks. The order of the interventions was random and the experiments were blind to the intervention until all data analysis was complete. Mean oxygen consumption (ml. min-1 STP) at rest did not differ significantly between the interventions, either BEFORE or AFTER the intervention (BEFORE [AFTER]: fasting 204 [214.2]; carbohydrate 217.5 [276.6]; protein 206.9 [225]). Mean oxygen consumption during exercise did not differ for the fasting or protein-rich interventions (BEFORE [AFTER]: fasting 806 [898]; protein-rich 727 [1020], p=1 and 0.071, respectively – one-way ANOVA with post-hoc Bonferroni). However, oxygen consumption during exercise after a carbohydrate-rich meal was markedly and significantly increased. Before the meal the average (n=13) was 786 ml O2.min-1 (range 270 to 1214) but after the meal the average was 1220 O2.min-1 (range 720 to 1740, p<0.0001 – one-way ANOVA with post-hoc Bonferroni). In summary the findings of this study are consistent with those reported by Miller and colleagues [2]. Oxygen consumption measured in the last minute of exercise performed at least one hour after a carbohydrate-rich meal was on average 62% than before the meal. Oxygen consumption at rest for the same intervention was higher, but not significantly. The findings could have value for those who wish to combine diet and exercise to control their weight.