Fast
Food
Learning to
Run with a
Bigger
Bolus, and
Other Gutsy
Strategies
for Marathon
Success
by Matt
Fitzgerald
In April 2002, a pair of great
runners ran highly anticipated
debut marathons in London.
They executed very different
race nutrition plans, and with
very different results. Paula
Radcliffe consumed nearly 40
ounces of sports drink on her
way to winning the race in
2:18:56, missing the world
record by just nine ticks. She ran
the last two miles in 10:10, faster
than her 5:18 average mile. Haile
Gebrselassie, on the other hand,
drank only water and not much
of it. He bonked late in the
race—running the last two miles
in 10:24, after maintaining a
4:45 pace—and finished a
disappointing third.
Could there be a connection
between Radcliffe’s more aggressive nutrition strategy and her
outrunning the greatest male distance runner of all time in the last two
miles of the London Marathon? You bet. It is a simple, incontestable
fact that the more fluids and carbohydrates a runner absorbs while
competing in a marathon, the better he or she is likely to perform,
especially in the critical closing miles.
Maximizing fluid and carbohydrate intake during a marathon requires
that you first "train your gut" during the weeks of formal conditioning
that precede race day. Unfortunately, this is something that few
runners—even few elite runners—think to do. Logging hundreds if not
thousands of miles in preparation for a marathon and then starving your
muscles through it is not unlike building an impenetrable fortress and
then defending it with the front gate open.
Never Enough
Runners are frequently ignorant of, or misled by advice such as the
American College of Sports Medicine’s recommendation that athletes
consume 30 to 60 grams of carbohydrate per hour during exercise.
These guidelines make it sound as if 30 grams are just as good as 60.
They also imply that the rate of 30 to 60 grams per hour matches the
rate at which carbohydrate is burned during exercise, for why would the
ACSM cap be set at 60 grams unless 60 grams were "enough"?
Here’s the reality. At marathon pace, a typical runner burns in the range
of 200 grams of carbohydrate per hour. But the average runner can
absorb only 60 to 80 grams per hour when carbohydrate is consumed in
the most absorbable form—a six to eight percent liquid solution. So the
ACSM guidelines are based not on how much carbohydrate you would
need to absorb in order to prevent depletion but on a very conservative
estimate of how much you can actually cram into your stomach without
suffering gastrointestinal distress (cramps, bloating, nausea). The vast
majority of runners don’t even get close to this.
The situation with fluid loss is similar. Body fluid (comprising water
and electrolyte minerals) is often lost at rates exceeding 1.5 liters per
hour during marathon-pace running. Yet the average runner is unable to
tolerate drinking at more than a third of this rate while racing. Drinking
any faster—even though the body could use a lot more fluid—causes
uncomfortable stomach sloshing and can eventually result in cramps,
bloating and nausea as well.
The bottom line is that you simply cannot get enough fluid or
carbohydrate while running a marathon. Sure, you could actually
swallow as much fluid as you sweat out and as much carbohydrate as
you burn, but it would only come back up the way it went down,
slightly warmer.
According to Christine Rosenbloom, Ph.D., and a nutritionist at Georgia
State University, however, "There are huge variations in the amount of
fluid consumption individual runners can tolerate and in the amount of
carbohydrate they can absorb while running." And you cannot know
how
much
your
body is
able to
handle—
thus you
can’t be
certain
you’re
consumin
g the
right
amount
of
nutrition
in your
next
marathon
—unless
you make
the effort
to
discover
it in your
training.
Also, as
with
every
other
aspect of running, practice helps. "By routinely trying to take in more
nutrition in training runs and perhaps also in the occasional shorter race,
you can learn to tolerate more than you could right now," says
Rosenbloom. For these two reasons, "training your gut" is essential for
optimal marathon performance.
How to Train Your Gut
The first thing you need to do is to start thinking about your bolus.
That’s right, your bolus. It’s a funny name for the contents of your
stomach. The reason it’s important is that, up to a point, the greater the
volume of nutrition in your stomach, the faster it empties. And the faster
your stomach empties, the faster the needed fluids and carbohydrate get
into your bloodstream. So it’s a good idea to practice beginning your
workouts with a larger bolus than you’re used to having.
It should be mostly sports drink. Liquids empty from the stomach faster
than solids and sports drinks are absorbed through the intestine faster
than other liquids. A good sports drink is also formulated to contain
only what working muscles need and nothing extra. Drink between 60
and 30 minutes before your workouts—especially your longer and
harder runs—and again five minutes before starting. Try to urinate
within 10 minutes of starting so that you don’t get the urge during the
workout. Begin with a modest amount. Even a few ounces may feel
uncomfortable at first, if you’re used to running on an empty stomach,
but keep doing it and you should adjust. When you do, try drinking a
little more before running, and continue in this way until you’re
confident you’ve found your personal limit.
Don’t use just any sports drink. In at least half your workouts, use the
drink that will be offered at aid stations in the marathon you’re training
for. If either your tongue or your stomach does not like this drink, or if
the drink is poorly formulated (more on this in a moment), use a second
sports drink of your choice in up to half your workouts.
According to Edmund Burke, Ph.D., and author of the book Optimal
Muscle Performance and Recovery, you should avoid using sports
drinks that contain fewer than 20 grams of carbohydrate per 12 ounces,
unless you have a very sensitive stomach. Avoid using sports drinks that
contain more than 30 grams of carbohydrate per 12 ounces even if your
stomach is cast iron, because such concentrated drinks absorb too
slowly. Burke also advises staying away from sports drinks whose
primary carbohydrate ingredient is fructose, which is digested more
slowly than sucrose, glucose and maltodextrin and is more likely to
cause stomach cramping. Be sure to use a drink that contains the
electrolytes sodium (100 to 200 mg per 12 ounces), potassium (100 to
150 mg per 12 ounces), and magnesium (30 to 70 mg per 12 ounces).
And lastly, avoid using sports drinks that contain "marketing
ingredients" like ginseng and chondroitin that cannot in any way fuel
working muscles.
Carry or give yourself access to your sports drink on all of your long
runs and marathon-pace workouts. Again, in your early workouts, drink
only a small amount that you know you can handle. In subsequent
workouts, gradually increase your intake until you reach the limit of
your tolerance, keeping in mind that it may take your body a few tries to
get comfortable with any given intake level. Increase your intake by
drinking more frequently, then work on drinking larger amounts at a
time so that you will maintain a larger bolus. Don’t drink more often
than once a mile, though, because you want to simulate the feeding
schedule provided by marathon aid stations.
In your early workouts you should test different brands and flavors of
sports drink, assuming you’re not a big fan of the marathon’s drink
choice. Start with a drink that’s heavier in carbohydrate content; if it
works well, use it, or another drink containing a similar amount of
carbohydrate. If it causes problems, go to a less concentrated drink. If
you can tolerate a more concentrated drink, says Burke, consider testing
out a sports drink that contains a small amount of protein in addition to
carbohydrate. Such drinks may reduce the amount of muscle protein
breakdown you experience during long workouts, so that you recover
more quickly afterward.
The Race Itself
In order to create your optimal marathon nutrition strategy, you just
need to know the maximum volume of sports drink consumption you
can tolerate before running and the maximum rate of consumption you
can tolerate while running. Having determined these numbers in your
training, simply duplicate them before and during your race, making
sure to drink between 60 and 30 minutes, and again five minutes before
the start, and at every aid station, if possible.
Now, of course, you won’t be handed measured amounts of sports drink
at aid stations so you’ll have to control your intake by gulp size. In
some cases you may need to drink only a portion of the contents of a
cup you’re given. If you have a high tolerance and are given a small
portion, you may need to take more than one cup at some stations.
Have confidence in the gut training you’ve done and stick to the plan
that’s come out of it. Then, during the second half of the marathon,
enjoy passing runners who didn’t train their guts.