IBD or not, avoiding processed foods/beverages, fast-foods, animal fat, caffeine, processed sugar is a smart diet and is strongly suggested for those with IBD, research has shown the above mentioned can exacerbate IBD symptoms.
I use, stevia as a sweetner when needed, instead of butter, I use extra virgine olive oil...instead of seasoning salts, I use fresh herbs to season my food, I eat natural foods, nothing out of a box or can....I mainly eat fish and chicken, beef on occassion (good for iron), I drink only chamomile tea and water, no coffee, pops, or juices with added sugar, on occassion I will drink 100% pure juices.
It seems obvious that what you eat will affect you, and depending on what you're eating will depend on how it will affect you...I'm able to tolerate all fruits and veggies so I don't have to ingest processed sugar.
The recommended daily amount of refined sugar and even salt are very minimal, people who mainly eat out of a box or can are getting hundreds of times more than the recommended amount and this I believe is what is leading to so many health issues for people, especially in north america compared to the rest of the world (which unfortunately in some countries are starting to jump on the bad diet bandwagon.
You are what you eat, that's for sure.
My bum is broken....there's a big crack down the middle of it! LOL :)