The best advice I can give is don't treat your body like I treat my minivan. Yes, I said, it. I drive a minivan....a 10-year-old one at that! What of it? Real men drive minivans. Right? Anywho...like I said, don't treat your body like I do my minivan. What I mean is don't always drive around with only a fourth of a tank gas. Seems like my "low gas" light is on more than it's off. So, to avoid that panicked feeling on a run, you know the one you get on a 20-miler when you realize you left your gel packs in the car (kind of like the same feeling you get when you're in the car-rider pick-up line at your kid's school and you're praying you'll have enough gas to get your kid and off the school grounds before the engine kills...not that I've ever had that feeling), follow the before, during, and after fueling and hydration tips below.
Before the Run: Eating before a run is important to ensure you have the energy you'll need to sustain you during your workout, especially if it's a hard or long workout. The trick is timing. You don't want to have hunger pangs but you also don't want cramps from running on a full stomach. If at all possible, it's best to eat 1.5 - 2 hours before your run. This will give your food time to digest. This means getting up a little earlier if you're a morning runner and eating a mid afternoon snack if you're an afternoon runner.
I know, I know, you're saying, "I already get up an hour or two before the sun even thinks about getting up. How can I mange to get up any earlier? And even if I do, I probably won't be hungry." I hear ya. Well, if your run is within 30 minutes, you'll probably be just fine on an empty stomach. I'd still recommend trying to drink a little water. If you're running between 3o minutes and an hour, I'd recommend drinking some sports drink. That way you'll at least get some fast acting "liquid carbs" in your system for some energy on your run. If, however, you're going to be running over an hour, I would still recommend getting up that 1.5-2 hours earlier. You'll need more in the ole tumtum for longer lasting fuel to sustain you on that longer run.
So you've got the timing down, now what should you be eating? Before a run, the meal/snack should be high in carbs. A little protein is good too, but keep the fat content low. Fatty foods can make you feel sluggish during your run. Some protein is good, but a lot can be slow to digest, contributing to a sluggish run as well. One of my favorite before run snacks is an English muffin toasted with peanut butter and a little jam. A great convenient store snack I've discovered is a Nature Valley Oats-n-Dark Chocolate bar and a banana. That combo is divine!
Hydration? Before the run, it's best to drink 16oz of water about 2 hours before the run. This gives the water time to pass through your system and for you to void it (pee) before the run.
During the Run: If you're running less than 1.5hrs, you really don't need to worry about eating during the run. If you've properly fueled prior to the run, you'll have enough energy to sustain your run. Most of your fuel in a shorter run comes from glycogen stored in the muscle. If, however, you're running longer than an hour, especially if you're running 2+ hours such as in a marathon, then refueling during the run becomes more important. Once you deplete your muscle glycogen, then you start to use glycogen stored in the liver. Nothing wrong with that. That's actually what's supposed to happen. However, just like your car will eventually run out of gas, your liver will eventually run out of stored glycogen.
Your body is able to store about 2000 calories of glycogen (fuel) which will take you about 18- 20 miles depending on your pace. I can hear those mind gears just-a-turning. Are you putting 2 and 2 together? 18-20 miles is about the time most marathoners hit the wall (if they're going to hit the wall). They simply run out of fuel and their body fatigues and the muscle firing fades away. SMACK! They hit the wall.
So, on those long runs, be sure to restock those glycogen stores along the way. Don't wait until you're on empty to try to fill them back up. It will be too late to do you any good.
So, how do you do this? Well, the simplest way is to start drinking a sports drink about 45-60 minutes into your run. Be sure to try a variety of sports drinks during your training to see which one works best with your system. (Never use a sports drink during a race that you haven't used during your training.) You can also use energy gels, bars, and some newer products that are similar to jelly beans and chews. Ingesting a sports gel about every 45 mins or about every 5-6 miles works well for most runners, but test out what timing or distance works best for you. The main thing is to begin the refueling before the tank gets empty. Some runners can tolerate solid foods during the run. I have one friend that takes a frozen Crustable (those little packaged PBJ sandwiches in the frozen foods section). By the time he's ready to eat it, it has thawed. Again, test out solid foods, gels, bars, etc. during your training, not during a race.
Hydration during the run? Well, if you're running less than an hour, water will do you just fine. Depending on how you perspire and how hot and humid it is, you may want to carry some water or stash some on your route. For runs longer than an hour you'll need to begin drinking a sports drink. After an hour of perspiring you will have begun to deplete your electrolytes (i.e., sodium, potassium, chloride, magnesium, phosphate, etc.). These are key ingredients in helping your body absorb the water you take in. Ever been on a long run and you've been drinking water constantly, but is just seems to be sloshing around in your stomach? That's probably because you've depleted your electrolytes and your body isn't able to absorb the water, so it just sits there in your stomach. Also, don't wait until you're thirsty to drink, that could be too late. Drink on a regular basis, throughout your run.
After the Run: Simple carbs and protein are key ingredients in recovery for runners. Most research says that a 4:1 ratio of carbs to protein within 30 minutes after a workout is optimal in speeding-up recovery and getting your tired, broken-down muscles the nourishment they need to rebuild and repair. Nonfat or lowfat chocolate milk actually has this 4:1 ratio and makes a great post run recovery snack. Be careful to keep the protein to a 4:1 ratio after a run because too much protein can slow rehydration and glycogen replenishment.
Hydration after a run? Each person is different and your hydration needs can vary from run to run depending on how much you sweat, the temperature, and your pace. Calculating your sweat rate is a great way to get a good handle on your specific hydration needs. To begin the test, weigh yourself just before a run. Then reweigh yourself after the run (before you change your clothes) and record the second weight. It should be less than the first. Each pound lost equals 16oz. of fluids. So, if you lost 2 lbs. on your run, you'd need to drink 32oz of water to replenish what you've lost. That doesn't mean gulp down 32oz immediately after the run, but it does mean to begin replacing what's been lost as soon as you can. If you're drinking the chocolate milk or a sports drink within the 30 minutes for refueling, those liquids can count as a part of your rehydration too. Do this test on several different runs (distance, pace, weather conditions, etc.). Then you'll be able to gage your rehydration needs for future similar runs when you're not able to weigh before and after.