Marathoner forever and I've be vegetarian over 22 years. Beans, veggies, fruit, nuts, spring water, herbal teas, rice, pasta, bread, nutritional supplements. Organic if possible. And lots of rest. Thom Jurek is an champion ultra marathoner and vegan. Read his books. Good luck! Keep us updated.
Long D. runners often have deficiencies in Potassium, Magnesium and yes, Sodium. So be sure to get enough of those. Else you'll have irregular heart beat and missing heart beats, both signs of low electrolytes.