The “wall” comes from running out of carbohydrate-based glucose. Some endurance athletes are switching to high-fat, adequate-protein, very low carb diets to change their metabolism from primarily carb-fueled to primarily fat-fueled. Even a lean athlete can store 10 times as much energy in fat as they can in carbs, getting rid of the wall in marathons. I got this info from “The Art and Science of Low Carbohydrate Performance.”
The “wall” comes from running out of carbohydrate-based glucose. Some endurance athletes are switching to high-fat, adequate-protein, very low carb diets to change their metabolism from primarily carb-fueled to primarily fat-fueled. Even a lean athlete can store 10 times as much energy in fat as they can in carbs, getting rid of the wall in marathons. I got this info from “The Art and Science of Low Carbohydrate Performance.”