Is your weight loss definitely connected to your IBS? You may want to consider going back to your family doctor for a physical and possible referral to other specialists, just to make sure that there isn't something else going on. I'd also recommend seeing a dietitian who can help you find ways of getting more calories.

Unfortunately, I don't know much about this, but I can recommend you check out HealthCentral's osteoarthritis site, as well as our IBD site - the latter may be especially helpful in terms of having a community that knows much more about this issue than I do. Try poking around on that site and asking some questions there.

Good luck! Please let us know how things go?