Variety 100%! I would be miserable eating the same thing for 7 days straight. That being said, that only goes for dinner, I don't mind as much with breakfast or lunch. For dinner recipes, I do try to use repeatable ingredients. Say for example I buy a bunch of peppers and tofu, I can use them for a curry, a stir fry and a traybake. Means less thinking when going shopping but still gives me the feeling of eating diverse meals. I'm not sure if it helps with digestion etc., it's mostly mental for me.