1. Taking in simple sugars during exercise is bad.
Sugar, in the form of glucose (and also glycogen, which is the storage form of glucose in the body), is the most important energy source for intense endurance exercise. Dozens and dozens of studies have demonstrated that supplementing your body’s supply of glucose/glycogen with glucose, fructose, and other simple sugars that are easily converted to glucose during exercise enhances performance in workouts and races lasting longer than an hour. Despite this mountain of evidence, many runners still avoid using sports drinks and energy gels containing simple sugars because they are accustomed to thinking of sugar as “bad”. But sugar is only bad when you’re not running. When you are running, sugar is good!