According to the latest study, which was published in January in Medicine & Science in Sports & Exercise:

exercising strenuously in the afternoon, depriving yourself of carbohydrates afterward, training gently the next morning and then swallowing a mound of pancakes might be a useful way to improve endurance and performance. The regimen seemed to have increased the athletes’ ability to access fat as muscle fuel, she said, allowing them to exercise harder during the workouts than the control group and gain additional fitness and speed.