It is an extreme measure, but it seems some people just cannot control their weight. There's a massive industry offering solutions. I'm lucky not to need them. I like some food treats, but I think I eat well in general and the exercise must help. We only get this one life and have to live it well. You have to enjoy it, but that does not have to mean constant junk food. I hope your friend gets on a better path after this.
!BEER
Obviously it is better to never get so fat in the first place and I wonder how people can care so little about themselves to allow that to happen to begin with. You have chosen the correct path in life, that is for sure.
I have a friend who struggles with her weight, but she finds it really hard to stop eating. She's tried all the diets and is currently on one of the new drugs that does curb her hunger a bit. If you get too heavy then it's hard to exercise.