Dr. Oz suggests starting with foods that don't need a label, like fresh fruits and vegetables. "If they're coming out of the ground looking the way they look when you eat them, they're good for you in general," he says.
You should also fill your grocery cart with items that are high in antioxidants, such as tomatoes, broccoli, kidney beans, blueberries, artichokes and prunes. "Whatever has that deep color like a blueberry, you know it's rich in antioxidants," he says. Try to eat five to seven servings of these foods every day.
Increase your intake of omega-3 fats to 3 grams a day. "Remember, 80 percent of our brain is fat," Dr. Oz says. "We need to have the right kinds of fats in our body to make sure our brain is the most resilient to stress and can learn the fastest." Some good sources include ground flaxseeds, walnuts, salmon, scallops, soybeans and squash.
Dr. Oz says the average American gets about 12 grams of fiber a day, but he recommends double that amount. Oatmeal, 100 percent whole grain bread, lentils, pine nuts, peas and raspberries are all great sources of this nutrient.
The last item to add to your shopping list is virgin or extra-virgin olive oil. Ideally, Dr. Oz says you should consume about a tablespoon every day. One nutritious—and delicious—way to eat olive oil is with tomatoes, made into a pasta sauce. "If you get that into your diet a couple times a week, you're getting these nutrients naturally."