Studies confirm that omega-3 fatty acids ease joint pain and decrease inflammation in the body — just what runners need. Flaxseeds are excellent sources of omega-3s and also contain fiber to keep you regular, which can prevent digestive pains and issues while running. Sprinkle some on your cereal or oatmeal, toss some in your blender when making a smoothie, or use it as an egg replacer for this protein banana bread. Not into flax? Salmon and walnuts are also high in omega-3s.