I personally don't think a diet aid is for anyone...the only proper/safe way to lose excess weight is strictly diet and exercise, it's the most effective and cheapest way as well as safest...my sister (whom doesn't have IBD) on occassion would drink those diet shake things and she said all it made her do was go to the can umpteen times more than normal for her, she even commented to me if that's what it was like having CD, I said basically yes, frequency is a big issue along with tons of other possible symptoms, she said the frequency issue was bad enough and she didn't want to even imagine what the rest is like.
Diet; portion control and proper food, not processed/fast-foods/junk foods...drink tons of water and cut way back (or out if possible) sugar. You can get away with over-eating fruits and veggies though, whatever you can tolerate, if you feel hungry indulge in fruits and veggies, they won't make you fat.
Exercise; for weight loss specifically you'll want to to a minimum of 30 minutes/day of cardio and a little bit of weight training too to help you tone (weight training also burns calories).
My bum is broken....there's a big crack down the middle of it! LOL :)