In the higher levels of food, they can buff 2 or 3 of the attributes or regen. So you get "Stacking" then. You start seeing two buffs on Blue recipes, and 3 buffs on Purple.
So, get a hireling for food and have them collecting Tomatoes and Oats for you, even if you don't' know the recipes yet. Tomatoes and Oats are used in Purple recipes.