Actually, like yellowfin said, it is all individual. You'll be stuck like the rest of us in a perpetual trial and error method of finding out what you can and cannot eat.
Many of us have found it effective to cut certain things out of our diet like sugar e.g. sucrose but not honey, gluten, high lactose dairy (milk but some of us build tolerance or already tolerate certain kinds of yogurt), and junky foods in general like those you pick up off the shelf. Preservatives and additives just aren't worth it...I follow the SCD as sort of loose guidelines myself and have noticed a tremendous difference. You might check it out either by its website and/or book.
Also, I would really recommend seeing an actual GI and getting more definitive testing done. I went to the ER for similar reasons and was misdiagnosed with IBS, sent home on the same diet, and prescribed medicine that ended up with difficulty breathing and hallucinations.
As for how to test your food? Keep a food diary or at least try (I forget a lot of days) and write down how you feel at different periods. Some foods you will know pretty soon after. Since you're on liquids right now it could be a good opportunity to start that since you will be gradually adding different foods to your diet. It's hard at first, but you do get the hang of it.
And like Nanners said, probiotics are a good way to go.
Nice art, by the way. The sculpting reminds me a little bit of Froud..not sure why. Maybe the lines in the Pharaoh's face. Froud always had a way of putting them in his subjects as well that added a lot of depth and character and I think you've definitely accomplished that as well.
20 years old, Diagnosed with moderate to severe Crohn's and Colitis in May of 2008.
Currently taking: Prednisone 10 mg, pentasa 2 pills 4x a day, bentyl as needed, omeprazole in the morning, prenatal multivitamin, humira every other week, and Align probiotics prescribed by my GI.
Diet almost completely without refined sugars, wheat, flour, gluten, high lactose dairy, and/or junk food in general. bonniegriffith.blogspot.com/
Learning how to live again.
"He who has a why to live for can bear with almost any how."