Poop: Does this food help me poop well (i.e. is it high in fiber - whole grains, fruits, veggies, etc.)?
Protein: Does the food give me significant protein?
Palate: Is it palatable, tasty; do I like eating it?
Pretty: Does it look nice - i.e. is it colorful (possess natural pigments, like in nutrient-rich foods)?
Obviously you should try to maximize on all four as much as possible. But it's fine if you sometimes go with only one or two. That is all. Try to get all of these in every meal, and listen to your body to see when it's full.
The end. I guess I don't need to write a book about that.