I am currently doing the elimination diet and have already tested quite a bit of things. Included in the things I've tested is sweet potatoes, garlic/garlic powder and carrots. They all gave me both digestive issues and cystic acne. They are all root vegetables so it just seems like root vegetables are something I should avoid. I mean I could test more kinds of them like radishes, turnips and whatnot but I think I'll just decide to avoid every single root vegetable for the next decade or two at least.
i vaguely remember hearing something about certain foods being high in types of vitamins which are bad for acne prone skin.i could be wrong but i think spinach was meant to high in iodine which is bad for people with acne.
i think there is some good information online if you do a google search.