Why and how you should put calories in during runs if you are a distance runner:
You run a race faster and longer than you usually train and with a bunch of adrenalin to boot. You do this with low blood sugar and you expect a good result? Not likely. Even the best breakfast is going to wear off after a couple hours of running and then your blood sugar will plummet if you don’t put more sugar in. The brain cannot store sugar at all so when your blood sugar gets too low your brain can’t work well anymore. Knowing this, the brain will try to stop you from using up what sugar is left in your blood by telling stories about what’s happening in the body. Bad stories. Low blood sugar turns a little soreness into aching pain. It turns a tightness you could have run on into something that feels like a torn muscle. It turns sniffles into the flu. I am not exaggerating at all and yet I’ve met very good runners who don’t seem to know that pain signals and the interpretation of them can change radically in response to blood sugar fluctuations. We wouldn’t be distance runners if we weren’t hard headed but there is a time and a place for that. Ever been so hurt and sick you staggered across the finish or didn’t finish at all but then felt a whole lot better that very evening? Consider your nutrition.
So now it’s time to talk about what I actually mean when I say “sugar”. I don’t mean table sugar. That gives you a spike and a crash and is no good for you at all. I do mean easy to digest carbohydrates. How much carbohydrate? No matter how much you put in, your body can only absorb 65-80 grams of carbohydrate per hour. Extra will just give you the runs after a while. Waiting until you really need the sugar means hoping your body can make up a deficit and since you can only absorb so much at a time, that’s going to be difficult and probably slow you down.
Do you need to max out on this stuff, put in as much as will absorb every hour? I don’t know, I’m not you. That kind of question has to be answered through experimentation during training. Whatever it takes to fuel your training, remember that since you run faster when you race you may want to pay attention to how many miles per gel instead of how many gels per hour so that you can better figure out what you’ll need in a race. If I ate one gel an hour jogging 12 minute miles then two an hour at 10 minute miles but then race at a 9 minute mile pace, I may need three gels an hour to race (and for me, I do if it’s going to take me more than four hours to finish). Also, trail running burns more calories per hour than road running because irregular surfaces mean more different muscles get used, especially for newer trail runners.
How do you decide which brand and which type of product to use? Go to a running store or even a cycling store and buy a bunch of different brands and flavors then test them on yourself DURING TRAINING RUNS not during races unless you want to risk a few ruined races. I love Hammer gel but some people hate it. I used to like Honey Stinger gels but the sweetness can be too much for me after a couple. A friend of mine can only use solids, or at least gummies, like Shot Blocs, but I don’t want to have to chew anything during a race. What if your stomach objects? Didn’t your legs object when you told them to run a new distance?
Your digestive system is full of muscles and enzymes with variable levels sort of like your legs. Your digestive system can be trained. When I first started running distance I had to eat breakfast at least two hours before runs and drinking water during runs without cramping up was hard for me. I kept at it. Now I can eat gels while I run. Oddly, I find that if I chew while the gel is in my mouth it seems to settle a little better or maybe more quickly. Crazy? Who knows, maybe my body wants an extra signal to tell it the glob of artificially flavored chemicals I’m swallowing is actually food.
Don’t like the taste of anything you’ve tried? If it doesn't taste great you'll wash it down with extra water and then you'll stay hydrated. Nothing wrong with a little extra reminder to keep putting fluids in. The other odd phenomenon I've noticed is that gels start to taste better as your body learns to associate them with feeling better. Do know that if you have trouble with stomach cramping or getting the runs during races or just after, Immodium will probably fix it. For anything longer than a 10K race I take two an hour or so before. I have a friend who takes an Immodium before any run of more than 8 miles or so because without it her guts are in knots for hours. The Immodium wears after five or six hours and digestion returns to normal.
Why not just tough it out during training and try to get used to performing with lower blood sugar? Okay, first of all, you need sit somewhere quiet and consider why you are trying to make ultra running even harder. I have spent a little time on that one myself and have gotten much better about water and calories and I think it’s one of the things that has helped me get faster this year.
On a more physiologic note, if you run at a moderate or better intensity for much more than an hour, especially more than an hour and a half, then, if you don’t put in any calories at all, your body will break down the muscle in your legs more than if you had put in just a little hundred calorie gel or something like it. This break down is not something that will make you stronger. This breakdown will only slow your recovery, causing subsequent workouts to have less intensity. This means you won’t get better as fast as you could. Running a border line amount of time and don’t want to carry stuff? Don’t start on empty and put something with carbohydrate/sugar back into your system right as soon as you stop (not after talking to your running buddies for 15 minutes in the parking lot).
This same problem of muscle breakdown happens with protein, by the way, only with protein it takes another hour and with protein you don’t need a whole lot. 5-10 grams will make a difference in a four hour run. There are protein gels like Accel gel and protein single serving solids and powders like some of the Cliff bar products or Hammer Perpetuem. If you don’t like any of those, consider that a Payday candy bar contains 7 grams of protein in addition to the sugar. Heck, put some nuts in a little Ziploc and chew one every now and then. I’ll write more about protein and running and solid food versus not solid foot on another day though because I think this is plenty to digest for one post.