Carb-loading: Pass the pasta?
As the day for the NYC Marathon (and others) draws near it’s time for runners to start thinking about fine tuning their nutrition. You obviously want to show up on race day with as full a gas tank as possible, but what’s the best strategy for doing this?
I first heard about the phenomenon of “carbo-loading” the way most runners probably have: through event organizers, charity groups and running clubs hosting giant pasta pig-out parties the night before a local marathon. The theory being that if you oink up on carby-goodness the night before, you’ll show up the next day with a full load glycogen to burn.
Unfortunately, as much as I love eating copious amounts of pasta, the science doesn’t really support this theory. It’s little more than a wives tale. Loading up on carbs during a single meal the night before a race will not have a significant effect on your performance.
Below is an overview of some different carb-loading strategies that are actually effective. If you want to know what I recommend, skip to the “on the road” section at the bottom.
How it works in the lab
Scientists, coaches and elite marathoners have been experimenting with sophisticated carbo-loading techniques that optimize race-day glycogen levels since the 60′s. All have measurable effects on performance. There are three leading approaches.
In 1960′s Swedish physiologist, Gunvar Ahlborg, found that the stresses of exhausting the body’s carb reserves forced it to over compensate when an athlete later ate some. He named this behavior “glycogen super-compensation” and recommended the following approach:
- Perform exhaustive workout 1 week before marathon (90 mins +)
- Consume a very low-carb diet (10%) or the next 4 days while training lightly
- Consume a very high-carb diet (90%) for the next 3 days while continuing to train lightly
It worked great. In fact, athletes were able to almost double their glycogen stores following this method. Trouble was, runners who tried it found that going four days on 10% carbs really sucked. Even the dedicated elite ones, found themselves tired, cranky and irritable. Not a great way to spend the week leading up to a big race.
Years later, scientists found that athletes could reap some very similar rewards without the irritating four-day depletion process. They prescribed:
- Perform a long, but not exhaustive workout 1 week before marathon (60 mins +)
- Eat normally (55 to 60% carbs) until 3 days before a longer race
- Consume a high-carb diet (70%) for the next 3 days while continuing to train lightly
Many scientists claim that the Ahlborg method is better, but when speaking practically, this method is much more realistic and manageable.
Western Australia Carbo-Loading Method
The most recent, and most realistic, approach comes from Down Under. In 2002 scientists at the University of Western Australia found that you could condense the whole week-long process down into one day. It works like this:
- During the pre-race week, eat normally while training lightly until the day before the race.
- On the morning of the day before the race, perform a very brief, but very high-intensity — 2 1/2 minutes at 1-mile pace followed by a :30 second sprint
- Eat a high-carb diet (70%) the final days before the race while training very lightly.
Pretty ingenious, no? None of that multi-day low-carb starvation with almost the same benefits of the Ahlborg method.
How it works on the road
All of the above methods will work on the road, but what’s realistic for a sub-elite marathoner? That’s you if you’re reading this blog.
Casual and/or first-time marathoner
If you’re new to marathoning or just looking to have fun and finish, simply following an easy, comprehensive three-week taper schedule while continuing to eat a healthy diet is really all you need to do.
You’re better off spending your time and effort focusing on training that teaches your body how to optimize energy at your race pace. For example:
- Two weeks out — Do a longish run that incorporates easy to moderate intensities followed by a few miles at race pace followed by a mile or two of cool down.
- One week out — Warm up for 10-15 mins. Then run 15-20 mins at race pace followed by a 1 mile cool down.
If you’re a seasoned marathoner and looking to break a challenging PR or trying to find a new edge, it could be worth experimenting with your carb-loading. For the reasons mentioned in the outline above, I wouldn’t recommend Ahlborg or the no-depletion methods. It’s simply not worth it especially when you have the Western Australia method.
That said, the classic rule of racing is “nothing new on race day.” But, when it comes to food and nutrition, I extend it this rule out to “nothing new on race week.” You don’t want to jeopardize all of your hard work and training on a new eating technique.
I suggest that you try the Western Australia method out on a B race or on the day of one of your long runs. This way you get a test it out without putting your main goal at risk.