Laura Wilson here, for About.com. Being a runner is not just about exercise. For your best performance and to increase endurance, living an all-around healthy lifestyle is essential. Sticking with a smart and nutritious diet, following these five guidelines, will help you make the most of every run.Eating small meals throughout the day will keep your energy level constant all day long. You’ll be less exhausted at the end of the day, and more likely to stick to your workout schedule. Smaller meals are more gentle on your digestive system, so you’ll be less likely to cramp during your run.Try to avoid processed foods, simple sugars, and saturated fat. If you are looking for quick energy booster, it is easy to cave and eat that candy bar - but you’re better off with whole grains, fruit, or protein that will stick with throughout your run and won’t spike your blood sugar. Also, the more fresh, organic foods in your diet the better - you’ll have more vitamins and minerals to fuel your workout.Many athletes try to "carbo-load" before a big race, but it is best to eat a balanced diet with lots of variety. Instead of getting stuck in a pasta rut, try potatos, legumes, and grains like quinoa, and brown rice -- all of which you can cook up with yummy and healthy veggies and lean meats.Staying hydrated doesn't have to all be about drinking 8 glasses of water per day. Mix it up with fruit juice, green tea, or drinks with electrolytes. My favorite is coconut water, an all natural and low-sugar source. Some foods are hydrating too -- fresh fruits like oranges, peaches, berries, popsicles, and even vegetables -- think how refreshing cucumbers and bell peppers can be.It never hurts to reward yourself for all your hard work and discipline. Rather than binge eating after a long stretch of deprivation, give yourself a little treat every day. Dark chocolate, frozen yogurt, smoothies -- all are guilt-free ways to indulge.These five eating guidelines for runners will help you live a healthy running lifestyle. Also check out our 10 healthy snacks for runners as well. For About.com, I'm Laura Wilson.