Men have more muscle mass is one thing. The flip side is that women have more fat mass--in an ideal environment, perfect food/stress/activity/sleep etc., an average healthy woman should have about twice the bodyfat of an average healthy man. If you take a woman and a man at bmi 30, more of that extra bodyweight is probably going to be fat in the woman than in the man.
https://www.bodybuilding.com/fun/berardi40.htm

There's a relation of lean vs. fat mass to the ratio of lean to fat mass that's lost during calorie restriction or fast. This is without taking working out and other factors into consideration. John Berardi has an article about this I've linked above. As a general rule, so of course there will be personal exceptions, the more fat you carry, the more of what you lose on a standard diet will be fat. So as women carry a higher percentage of fat, in general, more of the weight that they lose is going to be fat. So at a certain energy deficit, a man will lose more lean mass vs. fat when compared to a woman. Again, generally. And of course lean mass weighs more per calorie, much more, than fat does.