ObesityHelp is the largest and earliest board of this kind, as far as I know. There also are Yahoo groups, though I've never checked them out, I have heard people mention them. Do a search, and you'll probably come up with something.
It's not such a bad idea to check other places--you get second opinions for important stuff, right? -- but we admins/mods of the board sure hope you'll make this your home base, even though you may give other places a vist from time to time.