Ingredient lists are a good thing to look at. They tell you basics of what they put into the product so you can try and discern if this is something you might want to enjoy. Unfortunately more often than not there are ingredients that are going to create some reactions. Obvious ones like high argenine ingredients such as chocolate or nuts can make many people react even if all they ever had was chicken pox not to mention virus that cause cold sores, canker sores or herpes. Argenine rich foods can bring flare up these sleeping virus and create fatigue at the minimum if not a full blown outbreak..
Then are the hidden things masquerading as "natural" ingredients. This could be anything from bug parts used as dye to certain forms of msg.
The other bits of the label such as calorie counts or percentages of protein are not accurate and might even be based so far off that what you think you are getting you are not getting at all. The whole grain goodness that was in the original whole grain gets oxidized rather quickly once the grain is broken down into flour. The nutrients that could be listed could also be counter balanced by so much added sugars - even natural sugars or organic and natural sugars, that what you are really getting out of the product could have negative benefits and unfortunately that is the case with almost all processed foods. That doesn't mean I won't eat chips or crackers or things that are fun treats. I just limit my quantity and am choosey about what goes into my indulgences.
Remember the Pollan (cit)ation "Eat food, mostly plants, not too much."