Is it true that men lose weight faster than women?

Yes. What people call metabolic rate or your metabolism varies directly with muscle mass. Essentially, the more muscle a body maintains, the faster it uses calories. Men generally have more muscle than women so they lose weight faster.

yes

Yes testosterone

Of course.

Yes

Yes, alas. Women’s bodies tend to hold more native fat content. So generally speaking, if a man and woman of comparable size diet, he will have less fat to lose.