Amy Miracle, MS, MA, RD
Registered Dietitian & Exercise Physiologist

"Carbohydrate loading" is likely one of the most misunderstood concepts in sports nutrition. It is commonly thought that anyone involved in sport needs to "load up on carbs" by eating as much as you want in the days leading up to an event. Let's take a closer look at what is carbohydrate loading, who benefits from practicing carbohydrate loading and how it is accomplished.

What is carbohydrate loading?
Carbohydrate loading is a technique involving changing your pattern of training and diet to maximize muscle glycogen (carbohydrate) stores prior to endurance competition. When the technique was originally developed it typically involved a 3-4 day depletion phase and a 3-4 day loading phase. The depletion phase included an increase in training time and intensity along with a decrease in carbohydrate content in the diet. This is intended to utilize the existing stored muscle glycogen and thus prompt glycogen re-synthesis. The loading phase was intended to optimize muscle glycogen re-synthesis and in turn delay the on-set of fatigue in events lasting longer than 90 minutes. Further research has allowed the method to be polished so that current day carbohydrate loading is now more manageable for athletes.

Does carbohydrate loading improve performance?
Carbohydrate loading enables muscle glycogen levels to be increased by 50-100%. This extra supply of carbohydrate has been demonstrated to improve endurance exercise by allowing athletes to exercise at their optimal pace for a longer time. This dietary technique is not likely to make you go out faster but will allow you to maintain your pace longer.

How do you carbohydrate load?
Today's endurance athletes use a modified carbohydrate loading method. Ongoing research has demonstrated that the depletion phase is no longer necessary. This is a bonus for athletes as the depletion phase was very difficult. Today, carbohydrate loading should begin 1 week prior to competition. Exercise taper along with following a high carbohydrate diet (7-12g/kg body weight) is sufficient to elevate muscle glycogen levels.

A sample carbohydrate loading regime:

Day 1: 90 min. of training and 7 grams of carbohydrate per kg* of body weight
Day 2: 60 min. of training and 7 grams of carbohydrate per kg* of body weight
Day 3: 40 min. of training and 7 grams of carbohydrate per kg* of body weight
Day 4: 30 min. of training and 12 grams of carbohydrate per kg* of body weight
Day 5: 20 min. of training and 12 grams of carbohydrate per kg* of body weight
Day 6: Rest and 12 grams of carbohydrate per kg* of body weight
Day 7: Competition

Resist the urge to get in "just one more" long run or ride just prior to the event. You will un-do all of the beneficial storing of muscle glycogen that you have just worked to build!

What does a high carbohydrate diet look like?
The following is a list of foods that will help you achieve the carbohydrate loaded state you need to maximize your race day performance.

- low-fiber breakfast cereal with reduced fat milk
- bananas
- orange juice
- muffins
- sports drinks
- sandwiches with your choice of filling
- low-fat yogurt
- smoothies made with low-fat milk
- pasta sauce with cooked pasta

A note about women and carbohydrate loading
Most studies of glycogen storage have been conducted on male athletes. However, some studies suggest that females may be less receptive to carbohydrate loading, especially during certain times during the menstrual cycle. You should use this technique like any other dietary technique and try it out on a competition that is less important to you and practice, practice, practice.

Common errors made when carbohydrate loading
Many athletes that attempt to carbohydrate load do not do so properly and therefore do not garner the benefits. Listed here are common mistakes:

- Carbohydrate loading requires an exercise taper. Athletes may find it difficult to decrease their training the week before a competition. Failing to rest will compromise carbohydrate loading.
- Many athletes fail to eat enough carbohydrates. It takes a large quantity of food to carbohydrate load properly.
- Trying to go it alone. Working with a sports dietitian or using a carbohydrate counter can be useful.
- In order to consume the necessary amount of carbohydrate, it is necessary to cut back on fiber and make use of simple carbohydrate sources such as sugar, sports drink, jam, honey, jelly and canned or dried fruit. Athletes who consume lots of high fiber foods during carbohydrate loading may suffer gastrointestinal upset.
- Carbohydrate loading will most likely cause an athlete’s weight to increase to a small degree (~1 pound). This extra weight is due to extra muscle glycogen and water. For some athletes, a fear of weight gain may prevent them from carbohydrate loading adequately.
- Athletes commonly use carbohydrate loading as an excuse to eat everything and anything in sight. Consuming too many high fat foods will make it difficult to consume sufficient carbohydrates. It may also result in gain of body fat. It is important to stick to high-carbohydrate; low-fat foods while carbohydrate loading. The idea is to carbohydrate load not calorie or fat load.

* To convert body weight in pounds to kg (kilograms): pounds divided by 2.2.

If you have questions, feel free to contact Amy at amymiracle@aol.com or 702-203-2468.