#make fun of

Trust me, the large person you are about to mock is very much aware of their size. They think about it a lot, even without your helpful reminder. Your commentary will only serve to give them lifelong pain, even if they someday lose weight, and to temporarily satisfy your childish urge to be cruel, even if you someday grow up. Let it go, and look in the mirror sometime. You are far from perfect yourself, just like the rest of us.