I go with a combo of the 5 ingredient and the thought "Could I actually make this product in my own home." Like I do buy jam sometimes when I run out. But I can make it with the ingredients listed.
Sometimes I'll have more than 5 ingredients, although I think Pollan groups ingredients into categories (is there more than 5 ingredients in 8 grain hot cereal?)
But protein powder I wont because I have no earthly clue how to extract whey protein and turn it into powder.