Whatever else ultra running is about, optimal fitness isn't part of the mix. I say this as a former ultra runner who decided to face facts about the costs in terms of inflammation and oxidation. Look, if the euphoria of training for and finishing such events is your preferred source for inner/spiritual satisfaction (I can dig) then you can do your best to mitigate the damage with diet and supplements. Check out Hammer Nutrition. I have zero regrets about moving beyond ultra range and focusing on fitness oriented, longevity-favoring cardio and strength training. Plus, it was only after quitting that I realize how tiring it was to train at that level. Some of the least healthy (overweight, carb-loading, edgy, fidgety, exhausted) people I know, run 4-5 ultra events per year.
It is now clear to me how much beet I feel not consuming the quantities of carbs required for ultra training. Even low sugar carbs took their toll, in terms of a certain constant "amping up" that just didn't work. I am pretty sure getting off wheat has made a big difference in that regard. I definitely feel better, run better, and enjoy life more, when not constantly "fueling" for events I had stopped enjoying and that weren't serving my larger goals of extending healthy longevity. I still seek and enjoy peak experiences associated with physical exertion and other similar challenges.