Step1
Losing weight is not an end - it is a means. A means to what? To being happy, of course.
Enthusiastically disposed folks cannot help discussing their new toy with others - all the time. Most women going through a weight management program cannot help discussing it with, well, anyone. The jury is still out on whether that kind of behavior can jinx the program, but that's not the point.
Step2
Listen. You're overweight. You're trying to lose weight. That's all there is to it, really. There's nothing to discuss. If you want encouragement, your next door neighbor, your husband, boyfriend, kids, your mom, your girlfriends are NOT the people to turn to.
Part of the extra weight problem is that those who suffer from it spend way too much energy thinking about it, talking about it, paying attention to it. You should be popular, not your weight. Really. Do not accommodate your weight - do not talk about it; don't allow others to discuss it, either.
Here's how, and here's why -
Suppose you have a date with this cute guy who insists on assuring you ALL THE TIME that it's okay for you to be fat. He's just trying to be nice. Polite. Thoughtful. In reality, he's just being a moron.
Don't call him a moron - guys don't like that. Just let him know that you have other qualities (apart from being fat) - you're outgoing, clever, witty, fun, humorous, luminous, a good listener, a good storyteller, etc, etc. And you're definitely sexy. The gist of the message should be - "Yes, I'm fat. Now get over it and let's talk about something that's really fun, or funny."
Step3
Remember that your fat LIKES to be talked about. It ENJOYS attention. It loves the fact that you're not the only one thinking about it. Apparently, others think about your fat too.
Don't let them.
All those extra pounds - they won't leave unless you make them feel unwelcome; neglected; ignored.
Enthusiast 
