In terms of health, the gentle reader can find all we currently know about diet and its effect on health right here:
https://www.annualreviews.org/doi/10...-032013-182351
All the various forms of healthy diets can be summarized as "eat food, mostly plants, not too much."
After reading that, one will have to give a little thought to how these various healthy diets can be used to support an athletic lifestyle and high achievement. Basically, we don't go fast without a lot of carbs. The diet of a Kenyan marathon runner is about 25% white sugar. A rider I know who won the Furnace Creek 508 in ~24 hours went through 19 bottles of Ensure plus a good quantity of other high-carb drinks, all liquid food if I remember right.
We don't necessarily have to aspire to that level of achievement, but OTOH we don't want to be off the back. On our tandem, my wife consumes nothing except Ensure during rides. Otherwise, we eat a Med diet. Gotta do what ya gotta do.