The person who plans to exercise at an intense level for two or more hours should eat something a couple of hours before the activity. The goal of many exercisers is to burn calories. Skipping breakfast delays the process, while eating breakfast can jump start it, according to the Penn State newsletter. It's called the thermic or thermal effect of food. Eating an early morning meal results in calories being expended more rapidly than they would be without eating.
Evidence also exists to show that skipping breakfast actually lowers the metabolic rate.
Rosenbloom sees skipping breakfast among female athletes as a particular problem.