I see lots of talk about carbs and carbo loading. Nothing about fat intake.
Two months ago I did a rocky, 80 mile restart enduro fueled with bacon and yams. In my hydration pack was a home brew solution of water, a pinch of salt, and a squeeze of lime (electrolytes).
For last weekend's 80 mile hare scramble (28-mile loops), I added to this concoction (stored in bottles, not my pack), coconut water (electrolytes), raw eggs, canteloupe, strawberry, raspberries, and blueberries and blended them all up. This worked fine as I pitted each lap because the long sand washes had everybody burning gas at higher rates. Energy levels stayed up and I was well-hydrated as I was constantly tempted to pull over to pee.
I think I might add some fat to the drink (another egg or maybe some olive or coconut oil).