OBJECTIVE To measure caloric intake, physical activity level and resting metabolic rate in participants having the subjective opinion of either having a high or low metabolic rate. METHODS Recruitment by local advertising of healthy subjects feeling that they have high or low metabolism, i.e. either a tendency to easily stay lean ('high') or to very easily gain weight ('low') also when taking food intake in comparison with physical activity into account. Walking distance was estimated by pedometry, assessment of caloric intake was determined by food registration. Measurement of resting metabolic rate was performed in the fasting state. RESULTS We recruited 44 participants with a sense of 'high' metabolism and 12 subjects in the contrasting group. Subjects with 'high' metabolism were leaner ('high': 20.4 +/- 2.1 kg/m(2), 'low': 27.8 +/- 7.5 kg/m(2), p < 0.0001) and reported a higher caloric intake than those with 'low' metabolism ('high': 11435 +/- 2420 kJ/24 h, 'low': 8339 +/- 2679 kJ/24 h, p = 0.001). Despite this there was no difference in the measured resting metabolic rate between the two groups ('high': 7230 +/- 1233 kJ/24 h, 'low': 7430 +/- 1422 kJ/24 h, p = 0.6), nor was there any difference in physical activity measured by pedometry. Resting metabolic rate was negatively correlated with age and positively correlated with BMI in multivariate analyses of the total cohort. CONCLUSION The sense of having a low or high metabolic rate is not related to actual resting metabolic rate.