Your body is your vehicle, so you have to keep your engine running when you work out.This means fueling up your body by eating the right foods and drinking the right fluids, during the right amount of times.
The American College of Sports Medicine says, "Adequate food and fluid should be consumed before, during, and after exercise to help maintain blood glucose concentration during exercise, maximize exercise performance, and and improve recovery time. Athletes should be well hydrated before exercise and drink enough fluid during and after exercise to balance fluid losses."
**Please be sure to carry water with you. Ideally, you should take in a couple of sips of water every 2-3 miles.**
6 miles is a borderline distance for fueling and can be particularly critical for runners new to these longer distances. It is recommended to refuel with Gels (Gu, Honeystinger, Huma, Hammer, etc.), Sports Beans by Jelly Belly, or any kind of Gummy Chew (Gu Chews, Honeystinger Chews, etc.) or other food sources after about 40 - 45 minutes of exercise. Once you do refuel, it will take about ten minutes or so to get into your system. Depending on your ability level, you may or may not need to refuel on those longer runs. For half marathon distances, between miles 4-5 and miles 9-11 are ideal times to refuel. For marathon distances between miles 5-6, 9-11, 15-17, 19-21, and 23-24.
This is why you train and experiment with refueling options BEFORE race day to find what works best for you and your body's needs!
The more experienced you become at these longer distances, the better you will know/understand how to fuel your body.