Carbohydrates provide 60 percent of the energy required to make your body go, and whole grains are packed with complex carbs (the good kind!), which are full of vitamins and minerals. Eating whole grains can prevent a surge in blood sugar after your next meal, according to a study in the Journal of Nutrition and Metabolism, which means fewer energy crashes than when you eat refined carbohydrates in sugary or heavily processed snacks. Start your day with oatmeal or a high-fiber cereal to stay full until lunch, or snack on whole-grain crackers or granola bars for an afternoon boost.