C.G.
Ok, I can't find any product (ingredient) info on these jokers. I'm going to guess they have a lot of fiber (not soluble) so that's not going to be good for your IBS. Non soluble fiber does make you gassy which will irritate your IBS.
Any bar, in general, that has a lot of fiber/protein will make you gassy. I would stay away from them.
If you're looking to add fiber to your diet, whole psyllium powder is a soluble fiber that most GI doctor's encourage IBS sufferers to use.