It depends on how big of a part of your life they play.  If you see your parents every day and they’re very militant, then it would be hard to escape harassment from them.  But, as long as they don’t cook your meals for you, there’s not much they or anyone can do you stop you beyond that.

Same thing goes for friends.  If your friends are like mine and are equally as strange as you are, then they won’t care.  If they’re the kind of friends who will tease you mercilessly, you have to just accept it at first.  There’s no hiding it, but eventually your confidence will deflate them.  If you start to get teased because of your weight, you’ll find that you’ll take their ammo away by not responding negatively to it.  Eventually, it will just become who you are, and you may even start to like it.

Some people can’t really handle teasing and pressure, and that’s okay.  If you want it bad enough, though, the pros outweigh the cons no matter how bad they are.  Being fat will never be perfectly socially acceptable, and you pretty much have to embrace that.