I'm so sorry Gibby.

I have to say that if I had family getting down on me about something I am sensitive about, whether they're joking or not, and it bothered me that much, I would consider saying something. It would appear that your DH saying something to them about it has had no effect, so hearing it straight from the horse's mouth might be more effective.
You having laughed along before may have made them think that it doesn't bother you that much. Next time they mention it, you could gently say "Listen, I am trying to lose weight, but it's a very difficult issue for me, and your comments hurt me even if they aren't meant that way."
Or, if you're just not quite that confrontational, next time they say something about it you can actively not engage with it. If they shout something to you from the kitchen or the living room, pretend you didn't hear. If you're all sitting around the table or on the couch, change the topic, or smile and say nothing then make like you need to leave the room to go to the bathroom. They'll probably sense something has changed and there's no discussion if you don't play along.
I'm not saying to be passive aggressive, but there is certainly nothing wrong with being a certain kind of passive. We all say things because we want a reaction, whether it's laughter, connecting with someone, to hurt someone, anything. If they don't get a reaction, or get one they don't want or weren't expecting, they're less likely to try it again.
Hope that helps at least a little. Family stuff and relationships are so complicated. But go you for losing 10 lbs! A result is a result, no matter how big or small.
