That is what you need to find out for yourself. Sorry for being glib but everyone is different. The most popular triggering foods are gluten, dairy, and high fructose corn syrup, but any food can cause problems. To see if you are affected try forgoing each food for a few days to two weeks, one food at a time so that you do not get confused.
Try going a few days avoiding gluten (wheat and barley) and see if things improve. Next try avoiding dairy. A food journal can be very useful.
Male/59 DX ulcerative colitis Feb08, possible Crohn's colitis DX Mar10.
No Meds, allergic to Mesalamine. Remission since Mar10. Psyllium seed mixed with VSL3 especially helpful. Food journal instead of SCD.
Multivitamin, extra D3, K2, high gamma E, probiotics, fish oil, glutamine, magnesium, phos choline, resveratrol, S. Boulardii, boswellia, curcumin. Watch gluten, lots of fruit & vegetables (but no plums or kale), no soda, no HFCS, no trans fat, tea instead of coffee, no shellfish, few processed foods, no carrageenan.
Nature created all of the locks, therefore Nature has all of the keys