Why would a distance runner consume carbohydrate instead of protein before a race

Eating carbohydrates prior to a race improves a runner's endurance , speed, energy and alertness, according to Asker Jeukendrup, a professor of exercise metabolism and academic director of the Human Performance Laboratory at the University of Birmingham in the United Kingdom.

photosynthesis makes the glucose that is used in cellular respiration to make atp. the glucose is then turned back into carbon dioxide, which is used in photosynthesis. while water is broken down to form oxygen during photosynthesis, in cellular respiration oxygen is combined with hydrogen to form water.