Our weight isn’t the only thing that matters when calculating how many calories we need in a day. Body composition also matters. Muscle burns more calories than fat, even when we’re not moving. Someone with a higher percentage of muscle is going to need more calories than someone of equal weight who has less muscle and more fat. Since men’s bodies tend to be leaner and have a lower percentage of fat than women’s, this means that men of equal weight usually need several hundred calories a day more than women.
When men and women weigh the same and have the same percentage of muscle, their calorie needs are similar.