For one thing calories required is in part a function of size and men on average are bigger then women. Size also is a factor in simply walking, a 180lb man will burn more calories walking a mile then a 125lb woman would burn walking that same mile.

Men also have higher basal metabolic rates. I put a link to a webpage that calculates how many calories you need at rest. Notice there is a selection for male and a selection for females. If you set it to male put in random information and the change it to female the calories drop.

One of the reasons men eat more and still don't carry as much fat as women do is we just simply burn more calories. It hasn't been proven but many scientist suspect that the ego burns a lot of calories