There is no hard and fast UA nutrition strategy. Diet is very personal and what works for one person might be a disaster for someone else. We are all omnivores and try to eat fairly basic food with minimal processing. Meat, chicken and fish, dairy provide the protein, Fresh fruits and veggies for micro nutrients and card. Grains provide additional carbs and add to the simplicity and yumminess factor. Not rocket science really.
Something to keep in mind about diet is that humans are omnivores, meaning we can and do get by well on virtually any type of diet. The US 100mile record is held by Zach Bitter and he is a carnivore. Clear on the other end of the spectrum ultra running legend Scot Jurik is a vegan.
I have sat with Kilian while he downed copious quantities of sugary pastries for breakfast before a workout.
We do believe that fat adaptation is a benefit in ultra long events (more than a few hours continuous movement). People training a high volume (>15 hours/week) will be come fat adapted with little to no dietary restrictions. Those training under 10 hours/week can boost the fat adaptation process with some simple dietary manipulations like fasted morning aerobic workouts and restricting carbs a bit.
I hope this helps.