Monday, 23 April 2012

Carbo-Loading Before Your Run

Aside from tapering, carbo-loading is also one of those practices that a lot of runners think about but are never quite sure how to do properly.  For something as straightforward as ingesting more carbohydrates prior to running a marathon, it's actually not that easy to get it right. 

Also, some people swear by it and others...well not so much.

BUT if you are thinking about carbo-loading for your next race, here's a handy guide for you.  I hope I was able to simplify it down to a manageable level so as to encourage rather than discourage you from trying it.

The overall premise is that the glycogen stored in our bodies is good enough for 90 to 120 minutes of activity;  after that, you're on your own.  Some reasearchers claim that replenishing your carbs while racing is not all that effective because it takes time for your body to process it to a usable state.

Mayo Clinic writes that carbo-loading of 4g/kg of body weight is sufficient but a write-up by Alex Hutchinson (Sweat Science, Runner's World) in the Globe and Mail citing a London study says that up to 10g/kg is closer to the correct amount but most people are only able to consume ~7g/kg.  10g/kg is too much food for most people!

Runners who successfully loaded prior to racing ran 13.4% faster and slowed down less than the non-loaders in the final 7 kilometers. 

Another factoid to consider is that different types of carbs are absorbed in different ways.  For example, the carbs in pasta are absorbed via different channels in the body as, say, a sports drink.  In addition, the carbs in pasta are more complex and takes more time and calories to break down.  Ingesting different types of carbs at the same time leads to more efficient loading than eating or drinking more of just one type of carbs.

Lastly, there's a debate on what's more effective:  fueling days before the race or on the day before?  Some folks advice slowly stepping up your consumption 2-3 days before the race and then eating a normal meal the day before to prevent GI distress while others say load up on the day before.

Don't be worried if you gain a few pounds while loading...this is because 1 g of carbs absorbs 2-3 g of water.  You'll lose this water weight quickly enough as you're running your race.

So how much is enough?

Please note that I am not a nutritionist and the meals listed above are not recommendations but are simply illustrations of how much carbs are needed to reach the levels indicated.  It's a lot of food!   ﻿﻿

As you can see, eating 10g/kg of bodyweight is not easy, unrealistic even for most people.  Alex Hutchinson writes that one way that might help is to top up your carbs on the day of the race.  This is accomplished by waking up a few hours before the race and consuming a sports drink to restore the glycogen that was used up while asleep (needed to maintain normal brain and body function).

The experiment continues and I will attempt to load up for 2 days and then eat normally on the day before the race.  Let's hope it's enough to take me past the finish line without hitting the wall again (oh how I hate that wall).


  1. Hello Stan!
    So, what was better? 2 days of full load, and the eve with normal meals?
    Or full load the previous day?
    In 2 weeks is my major competition: 80 km trail running, and the carbo load is very important...


    1. Hi Jorge. Wow 80 km in trails, now that's a nicel ong run :) For me personally, the last two marathons went really well and I attribute a bit of that success in eating properly before the race. The most effective way I've found so far is to start eating extra carbs on the dinner two nights before hte race.

      Example is if the race is on Sunday then start your foodfest on Fri night and this continues on to Saturday breakfast, morning snack, lunch, and midafternoon snack. It does get tiring eating that much food but it is necessary in my opinion.

      Have a regular dinner on Saturday night. I find that I have no stomach problems this way versus eating one big pasta dinner on Sat night.

      I also found that eating a variety of carbs is more effective. I mix it up with pancakes, potatoes, rice, bread, etc. Protein of course is still essential as some studies have shown that proteins and carbs when taken together is abosrbed more efficiently in the body than when taken alone.

      In the morning of the run, I wake up 3 hours before the start of the race and top off my supplies by drinking two bottles of a sports drink and a peanut and jelly sandwich then going back to sleep if I can. I then take a coffee one hour before the race and I'm good to go. Please understand the coffee is a personal thing (I enjoy it too much) and some people do not advocate this. The peanut butter and jelly sandwich though is non-negotiable. I find it provides the extra energy I need for the race.

      Good luck, taper wisely, eats lots, and have a great time! I hope we get to hear about your run.