So there are differences in BMR even when comparing two subjects with "the same" lean body mass. The top 5% of people are metabolizing energy 28-32% faster than individuals with the lowest 5% BMR. For instance, one study reported an extreme case where two individuals with the same lean body mass of 43 kg had BMRs of 1075 kcal/day (4.5 MJ) and 1790 kcal/day (7.5 MJ). This difference of 715 kcal (67%) is equivalent to one of the individuals completing a 10 kilometer run every day.