Given that food is fuel, it's only natural to wonder if certain types of food deliver energy more efficiently than others. Beyond the importance of eating a healthy diet that includes plenty of fruits and vegetables, whole grains, and healthful sources of fat and protein, there's relatively little scientific information about the effects of specific foods on a person's energy level. However, certain foods can give you more energy under specific circumstances.
Because muscles burn carbohydrates first, tests of physical endurance require a steady supply. Sugar is a simple carbohydrate, which means that it's digested and absorbed into the blood quickly. When you eat a candy bar or some other sugary food, your blood sugar shoots up. Your pancreas responds by flooding your bloodstream with large amounts of insulin, the hormone that carries blood sugar (glucose) into the cells. You feel more alert and physically energized. But the effect is short-lived, lasting only about half an hour, because the insulin rapidly lowers your blood sugar. Afterward, you may actually feel less energetic than you did before eating the sweet snack, probably because of the rapid drop in blood sugar.
To keep your blood sugar and energy levels on an even keel, pick your carbohydrates wisely. Try to avoid highly refined carbohydrates, such as white bread, white rice, processed pasta, and white potatoes, which are digested and absorbed almost as quickly as refined sugar, providing the same short-lived surge of energy and subsequent energy drop. It's better to choose complex carbohydrates, such as high-fiber whole-grain bread, brown rice, whole-grain pasta, and most vegetables. These take longer to break down, so your blood sugar levels rise and fall more gradually.
For more on developing self-help strategies for boosting your energy, purchase Boosting Your Energy from Harvard Medical School.