>I am lactose intolerant and gluten intolerant until I leave the US
Processed dairy and refined grains. They strip all the other stuff out and make it as sugar-packed and concentrated as possible for flavor reasons. Buy whole grains (the actual grains) from local suppliers. These are typically for feed for animals and "not fit for human consumption". But if you use those, your gluten problems will disappear.
Dairy straight from cows is a no-brainer as those are the people that the fuzz goes after all the time. So it should be obvious what the problem is with American food. Like, really obvious.