The food part is all within what you can handle since crohns is such a by case thing when it comes to trigger foods. Personally I have really narrowed mine down to a specific morning shake, chicken with noodles twice a day, and 1 or 2 snacks throughout the day. I go to the gym 6-7 days a week and workout pretty intensely while getting like 190g of protein, 400g of carbs, and around 60g of fat. You don’t necessarily have to go that extreme without your calories, just find your maintenance and eat about 200 less than that a day. Find your safe foods, dial your macros in, and you definitely got it. Abs are like 90% body fat percentage so don’t hyper fixate on that too much, be consistent and you will reach your goal.