I have the same issues with food and PCS. Beef fat is awesome and then every other fat is decent to ok for me. Sugar is really bad along with preservatives and highly starchy foods. I can't eat anything with sodium nitrite in it, this includes most bacon. My only suggestion is make sure your eating clean, like no fast food or eating out as you won't know what is in your food. Pay attention to ingredients and start whittling it down.

Strip your diet back to all natural and start eating the same breakfast everyday, do the same with your lunch and dinner for a few days then start adding one thing in at a time and recording. Its way easier to pin point with a clean diet and adding one thing at a time.

I couldn't do chips, candy, fastfood etc. The one thing that I could do was a tuna sub at subway.