Whole-grain breakfast foods, including cereals and breads, provide long-lasting energy because they are high in fiber, explains Today's Dietitian. Most fruits, especially berries, are also a good source of sustained energy. Incorporating various types of bran, nuts and seeds into breakfast also supports energy that lasts.
High-fiber foods keep the body energized the longest because the body digests them the most slowly, notes WebMD. The longer food takes to digest, the longer the period of available energy that food has to offer. Similarly, because hunger can lead to low energy, high-fiber foods provide lasting energy by allowing the body to feel full for a longer period of time.