Vagetarian -- It's a good question you pose. It certainly would seem that eating locally grown produce in season is the best way to go from a naturalistic point of view. And, to a large extent, I agree with this philosophy. But, it is important to get a varied diet almost every day. This would include some veggies, fruits, legumes, nut/seeds/avocado everyday. Now, it is healthy to vary the foods within those groups each day so as to get a wide variety, but it is still best to get something within each group everyday (or at least every other day). The only reason to eat not locally grown foods is to vary the diet, and get even more nutrient dense foods (e.g. pomagranate, blueberries, raspberries, kale or whatever else you may not be able to get locally).
So I like eating locally grown foods while adding in other very healthy foods grown elsewhere if they are not grown locally. And, it is important to eat the whole variety of foods (although within the veggie category it doesn't have to be brocolli or carrots more than once every few weeks if you are also eating other veggies like kale, collards, rapini, spinach, chard, romaine, mache, purslane, zucchini etc.) every day if possible.