Just like fat didn't have a good reputation for awhile due to X, Y, Z - be weary of your sources.

I use my own experience with Igg food sensitivity testing and removing those foods to see how I felt after. After allowing my system to calm from the foods then reintroducing just one of the foods that I was conditioned to the discomfort of, it let me see how much discomfort/pain different foods that showed up on the Igg test that make me feel horrible.