I have recently read four articles that talk about the importance of taking in carbohydrates during a marathon. It seems like it is not just important, it is a major factor determining whether you have a good or poor race (that is, how you feel the last hour of the race.
The carbs that you have loaded in the previous days and on the race morning are expended after 90 minutes of running. So you have to take in more. As well as more liquid. Actually, you can't take in as much carbs as you are burning (as much as 200g per hour) but you should try to take in 30-60g per hour. Unfortunately, this is as much as your stomach can handle. The thing is, some people can handle 30 and some people can handle 60, so you really should experiment before the race. Also, practice helps you to be able to handle more.
One Weider Energy gel has 45g of carbs. One Fightman Energy gel has 46g. I tried carrying a Weider gel last sunday on my long run and drank it between 20 and 25k. It worked fine (thanks for the suggestion, Mika). Not particularly troublesome to carry and easy to drink. Also they have a cap so you can drink a bit at a time. Carbo Shotz (available at Art Sports) have 29.8g. They are easier to carry (thin so you can stick them in your shorts) but harder to drink (thick and gooey and no cap, you should drink water from an aid station together or just after...your stomach cannot handle 30g of carbs all at once).
I will probably carry one Energy gel and two carbo shotz. (I will also carry some candy (glucose...high glycemic index for fast absorption by the body) although chocolate will be available at some aid stations, this was written in Courir, which I will also eat.)
The other way to take in carbs is via a sports drink. Ideally you want about 25g per 500ml, but most Japanese drinks have much less. Pocari Sweat has 6.7, I think it is. Of course, you are getting liquid as well. So not much carbs, but better than water. Again, you should experiment with your drink before the race.
Which brings us to the important point of...what will be the sports drink at the Tokyo Marathon? Does anyone know? I mentioned Pocari Sweat because Otsuka Seiyaku is one of the marathon sponsors, so I am guessing that PS will be the drink at the aid stations. I hope it is. It is drinkable and has the carbs and has some minerals, which is also good.
In summary, you should drink small amounts frequently after the race starts, and take in carbs, as much as you can handle, after 90 minutes. Oh, and eat a high carb breakfast: cereal or oatmeal or bagel or rice or guess what? instant noodles (low glycemic index for longer absorption by the body) and sports drink. Some people say a banana is also good, some say it is not so easily digested. I will stick with oatmeal. Again, you should experiment before the race.
Bob
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5 comments:
Thanks for the good post, Bob. Nutrition issue is very important for marathoners.
I usually carry two GU gels vanilla beans flavor, which are similar to Carbo Shotz or Energy Gel, concentrated carbo paste, one in my pocket and one in my hand. I also carry a few candies for emergency, but usually simple sugar staff is not recomended before or during the race because your blood sugar level goes up too quickly and then goes down as a reaction.
As a Japanese, I eat mochi (rice cake) for race day morning. It's very digestive and concentrated carbo, but above all it's psychologically good for me. We Japanese believe that you will get extra energy when you eat mochi. Highly recomended for everyone, but don't get it stick in your throat!
I do not know if these gels are available in Japan yet, but I have been using carb-boom (www.carbboom.com) and I think they are great. Easy to digest, nice flavor, and a good consistency in the mouth.
Dan (in Washington, DC)
If somebody wants to play with the Gel Calculator...
Just don't forget, the last gel should be taken no later than 45-60 min before the expected finishing time since it takes time to break down the carb and use that fuel. Anything taken later will only give a mental boost but no fuel that can be used in the race.
And also, if you need additional carbs at all depends a lot on your height, weight and predicted time. The ability to store carb does not increase linear with your height. In other words, smaller runners can store relatively more carbs in their muscles than taller runners.
A 160cm slim 2:30h runner may not need any additional carbs during a marathon, whereas a 190cm guy with the same time will have to refuel.
On top of all that I am not even sure if we're not marketing victims. In a self-experiment I once ran a marathon and used only pure water - I finsihed in my 2nd best time ever. Just a thought. Greets, Ingo
It really has a LOT to do with your training and the extent to which you have trained your body to utilize fat for energy. The long slow runs, especially if done on low fuel reserves, are best for that. If you haven't done many long runs or do your long runs with lots of fuel, then you probably haven't trained your fat-burning system so much and will really need those carbs.
I have also read that having simple sugars running around in your blood reduces the efficiency of the glycogen energy pathway -- i.e., glucose coming in from the gut somehow makes you burn glycogen more quickly. The upshot of this theory is that you should have lots of glycogen stored up from previous days carbo loading but have an empty stomach when the marathon starts. Then, you don't take any carbs until your glycogen is running pretty low. I suppose that is the 90 minutes mark that Bob talked of.
I am not necessarily advocating this strategy, just passing it on. I will say that the only time I tried it was in my PB at Ohtawara in '05. But I also trained exceptionally hard and was definitely in great shape, so I can't just say that it was down to this. All I can say is I used it and it didn't hurt me. I think I'll try it again at Tokyo. So if I have some oatmeal, it would very early, say 4:00 am, and that would be my last meal and I'd go back to sleep for a couple of hours. I would then throw down two or three gels between 25km and 35 km.
Matt Fitzgerald contributes to Runner's World and Running Times Magazine and has authored the book "The Cutting-Edge Runner". In these sources he has said that a well tapered, highly trained runner will have 800-900 grams of carbs in their system. At marathon pace a runner will typically use 200 grams per hour. Therefore, we should have plenty of carbs for a 4+ hour marathon right? Not necessarily. Evidently your body won't let the carbohydrate levels get down to a dangerous point. Fitzgerald also suggests that with the intake of carbohydrates, the carbs already in the system will be used more slowly and the brain will compensate by letting you run faster. This doesn't really say a whole lot I guess but I thought it was interesting. By the way, Fitzgerald is a big proponent of in race fueling for halfs, marathons and even interval workouts. I'll definitely do it.
AZ
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