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.

Everyone is different, I tested many things on runs before hand. Which distance are you doing? Many people don't stay strict paleo during ultras, but I do. I just did Javelina Jundred 100 miler strictly on paleo fueling. Dates, bananas, oranges, coconut water, nuts, plums all do well for me. Many raw items at whole foods work. Go raw bars, lara bars, laughing giraffe balls, ect. Paleo diet for Athletes is an amazing book to read. If you want to keep gels with your fueling, HAMMER is most natural and won't put you in a spiral like some high sugar things would.

Also one great about paleo and ultras, is minimal inflammation! I can run 50 miles and not even feel it the next day. Or as I said I jus did JJ100 and am walking and even jogging the day after, no pain. Important to keep paleo after the run too, and hydrate

I'm a marathoner & ultra-runner. There are at least two different brands of Almond Butter that are now available in 2 oz packets - perfect replacement for gel. The brands are Justin's and Artisana.

Make sure to get enough carbs before, during and after running preferably from fruit, honey or simple sugars.

I'd check out crossfitendurance if you haven't already. The guy who started it told me he'd done an ultramarathon without training any distances longer than 15-20 miles.

I think the comment about inflammation is key. (I used to be a runner. Lots of injuries and felt tired all the time.) Be ultra aware of how you're feeling, in your joints, your appetite, even your skin, etc. Ice, stretch, drink ridiculous amounts of water and continue to build strength, if you already were. Magnesium is great. Also, you can eat cherries, fresh or dried, or drink the juice, which helps with inflammation. You could start using some herbs that nourish the adrenals, so that you're working with any damage you might do daily. Happy trails.

For day-to-day training: potato, plantain, banana, and orange juice have all worked very well for me. I would say supplemental Vitamin C is important as well as magnesium if not for performance for recovery.

Hey man, not sure if you're still interested in this subject - but check out Phil Maffetone (.com). He's an Endurance legend who has trained the likes of Ultra Runner Stu Mittleman, Mark Allen & Mike Pigg (triathletes), as well as formula one drivers and stealth bomber pilots. He's all about connecting fitness with health and argues that this is entirely possible with an appropriate approach to training and health. his book the Big Book of Training and Endurance is a tome of goodness. While he's not strictly paleo, he's pretty paleo-friendly and with some slight alterations and an "Experiment of One" you'll be fine. I ran two 100km Trail Ultra's this month, within 2 weeks of each other and got faster. I'm doing a 50km this weekend.

Let me know if you want more info.

Cheers Tegyn