One of the best foods to eat to fight stress is avocado. Avocado is a great source of protein, essential minerals, vitamin E and vitamin C. It also contains potassium, fiber and healthy fat. Avocado helps keep the nerve cells and the brain cells healthy and help to reduce your stress levels. Moreover, avocado may help lower blood cholesterol levels and reduce risk for heart disease. You can eat avocado fresh or add it to your salads and smoothies.