PreRaceNutrPrep

I once had an athlete call me her secret weapon after she successfully completed an
Ironman event. I believe this was mostly due to the advice regarding her nutrition leading up to
the race. My key message was to emphasize carbohydrate rich foods and not worry about
gaining weight the week prior to the race.

The following defines carbohydrate loading, provides guidelines about how to execute a
carbohydrate load, and gives tips about hydration and race day nutrition prior to a major
event.

Carbohydrate Loading
Many athletes know that they should carbohydrate load prior to endurance events.
Unfortunately very few athletes truly know what this means and how to properly do this. In
sport medicine terms, carbohydrate loading is a "practice that aims to maximize or
supercompensate muscle glycogen stores prior to competition". Muscle glycogen is the
storage form of carbohydrates found in the muscle. Glycogen is also stored in the liver, but is
not as readily available for muscle metabolism during exercise.

Carbohydrate loading is beneficial for events that last longer than 90 minutes. It can improve
an athletes performance by 2 to 3 % through prolonging the time to exhaustion. The most
widely used method of carbohydrate loading includes 3 days of a high carbohydrate diet, in
addition to very light or no training or exercise.

Choosing Your Carbohydrates
The amount of carbohydrates needed for carbohydrate loading ranges between 7 to 10 grams
per kilogram of body weight per day, or between 400 to 800 grams per day. This results in
total calorie intakes of 2200 to 4200 calories per day, with 70 to 80% of the calories coming
from carbohydrates. Click here for example meal plans that provide two different athletes with
just over the minimum recommendation of 7 grams of carbohydrates per kilogram.

A carbohydrate loading diet requires changes to usual eating habits, including the choice of
breads, fruits, vegetables and beverages. Many athletes normally choose higher fibre breads
and cereals, and whole fruits, and limit their intake of fruit juices and sweets. Due to the
amount of carbohydrates needed while carbohydrate loading, the amount of fibre consumed
can be higher than a person is use to. This can cause increased gas, bloating, and potential
problems with diarrhea on race day. It is a good idea to choose lower fibre carbohydrate
sources such as white cereals, breads and grains, and juice rather than whole fruit. Choosing
beverages that contain more carbohydrates such as sports drinks or regular pops, can be an
easy way to increase the total amount of carbohydrates consumed during the day without the
added bulk.

Carbohydrate loading should be only a temporary diet change. Once the race is over, go
back to healthy eating habits that include whole grains, fresh fruits and vegetables.

Carbohydrate Loading for Women
The majority of studies on carbohydrate loading include males only. Research regarding the
benefits for carbohydrate loading for women is ongoing, but there is suggestion that a
women's menstrual cycle may play a role in how much benefit she obtains from carbohydrate
loading prior to events. Regardless, a common mistake that women often make is practicing
restrictive eating habits prior to an event in an attempt to avoid weight gain associated with
the decrease in exercise that occurs prior to major races.

Race Morning Nutrition
The meal consumed on race morning should be considered fine tuning the nutrition
preparation you have done over the past 72 hours. The meal should be low in fat and fibre,
and moderate in protein. The goals of the meal are: 1) to continue to fuel muscle glycogen; 2)
restore the liver glycogen that was used over night; 3) ensure optimal hydration; 4) prevent
hunger, and 5) provide psychological relief.

It is a good idea to try to consume the meal 2 to 4 hours before the start of the race, and
ensure there are adequate carbohydrates in your meal. As a guideline: If consuming the meal
4 hours prior to the race start aim for 200 to 300 grams of carbohydrates. If eating the
pre-race meal 2 hours prior to the race start, aim for 120 to 150 grams of carbohydrates.

Hydrating for the Big Day
Additional fluid is required to store carbohydrates as muscle glycogen, it is therefore
important to keep well hydrated throughout the carbohydrate loading phase. You may gain 2
to 5 pounds during the carbohydrate load, due to the fluid weight that is gained. Although this
can be concerning, the benefit of the carbohydrate loading is greater than the consequence of
a small weight gain. In addition, by the time you are on the run portion of the race, your
weight will have likely decreased to near normal status.

During the 24 hours prior to the race, place more attention to your fluid intake. Monitor how
often you are going to the bathroom and ensure that it is very light in colour.
On race day it is important to ensure you are well hydrated prior to the race start. On the
other hand many athletes drink more than is required due to nerves. This can result in
excessive trips to the washroom. (Although this may be of little consequence if you are bold
enough to warm up your wetsuit during your warm up swim.)

A guideline for pre-race hydration includes 400 to 600 mL (14 to 21 ounces) of fluid at your
pre-race meal and 250 to 400 mL (8 to 14 ounces) at the race site.

Putting it all together
Just as it is wise to avoid trying any new equipment on race day, it is also advisable to not
try any new diet strategies. If you have never tried carbohydrate loading before, it is a good
idea to try at least one day of eating a carbohydrate loading diet 24 hours before a (less
important) race or long training session. Race day meals and hydration strategies can be
practiced before early morning training sessions or at the same race you try the 24 hour
carbohydrate load. Having a tried and tested pre-race nutrition plan can be your secret
weapon for the next big race.

References:
Robins, A. Nutrition recommendations for competing in the ironman triathlon. Curr Sport Med
Reports 2007, 6: 241-248.
Burke, L. Clinical Sports Nutrition. 2nd ed. Chapter 13: Preparation for competition. 2000.
McGaw-Hill, Australia.

Any questions or comments are welcome and can be forwarded to
kimyoung.RD@gmail.com.