While you are in a flare is it possible to exchange the energy bars for a liquid meal replacement? There are low-glycimic, high protein drinks available that should meet your energy requirements without risk of exacerbating your symptoms. Keep looking and you will find something that supports your fitness goals and is easy on your bowels. No matter how much the disease takes you backward in your training, everytime you can get on that bike, it is taking you a step towards wellness. Good for you!
If you have ulcerations and are in a flare that is causing diarrhea and/or pain you might want to restrict the amount of insoluble fibre (skins, peel of fruits, nuts, coconut, popcorn, raw fruits and vegetables etc) this type of fibre is difficult for the body to digest and it tends to hasten bowel movements (and cause a lot of pain for anyone with strictures.) It's the soluble fibre that can accomplish what Pb4 was talking about. Soluble fibres (the kind of fibre that absorbs water) do break down in the bowel and form a gelatinous mass that actually can slow down and bulk up the stool, easing diarrhea. If you don't have a stricture, the extra bulk shouldn't cause you pain. Just about all plant sources of food have both kinds of fibre in some degree or another, but things like oatmeal and whole wheat are among the food sources that have high levels of soluble fibre, whereas popcorn, coconut, lettuce, etc have high levels of insoluble fibre and tend to actually hasten the passage of food through the system.
Think of what you have described is going on in your bowel, angry large ulcers. Now imagine undigested chunks of carrot, popcorn kernels, nuts etc scraping against these sores as they are being carried through your bowel. Compare that with the thought of a gelatinous mixture of oatmeal or peeled apple.. If you had a bad blister on your hand, would you moisturize with a foot scrub made of peach kernels?
30+ years living with Crohn's.