I heard so much about Spanx that I decided to try a pair. These will NOT make you appear any thinner. In fact my slacks were tighter with the Spanx on because the fabric is so heavy. They will smooth out any little muffin top that you have. I'm slightly over weight and wear a size 10. I cannot imagine these working for anyone who is obese and think that this will make them a size or two smaller. They will smooth out your rolls, but that's about it. The little opening in the crotch is useless for toilette purposes. You would have to take the whole thing off to use the bathroom. That is no easy chore. I suggest not eating or drinking too much while wearing these.