Why do fat people wear their pants so their fat hangs over in all directions?

Hey, I don't mean to offend people, I just don't know of a politer way to put it. My friend got gastric, she is 200 pounds and bragging how she fits into a size 12. When she said that I didn't believe it for a second, I was a size 9 after I had my baby and no where near her size, but I did not say anything. Well we were hanging out today and she bent over and ATLEAST one entire inch of fat was hanging over on her back side, and many more inches in the front. I don't get that. You really AREN'T a size 12. I have been big(ger) when I had my son I gained 50 pounds, and I NEVER EVER let my fat hang over my jeans.... I just don't get it?