Carb loading prior to running a marathon or any long distance event is important. We all know it or have heard it—your race begins before you toe the line of any event. The weeks, months, and years of preparation descend on to one day, one event. Your race performance is multifactorial. Genetics, training, experience, and diet all play vital roles in your race day performance. Italian restaurants are subject to hoards of endurance junkies looking to top of their tank with vital nutrients, all in an attempt to ward off the inevitable 20 mile “wall”.
Unfortunately, most athletes are unsure of how much, how often, and how far out they should begin shoveling down bowls full of stringy noodles and loafs of bread. There’s a science to it, a protocol if you will. Blindly throwing pasta dinners into your diet is much in the same as a random and ill planned training program. As marathon runner Bill Rodgers once said,
“More marathons are won or lost in the porta-toilets than at the marathon.”
Below, we present the research behind carbohydrate loading, or “carb-loading”. Remember, you should use foods that work within your diet. Trying new foods or concoctions can ruin your race day (see quote above).
How are carbohydrates used?
Simply put, carbohydrates are the primary energy source of endurance activities. They drive fuel your endurance engine. Carbohydrates are broken down within the body and stored as glycogen, or stored glucose. Think of your glycogen reserve as your gas tank. It’s a fuel reserve.
Like a car, the faster and longer you go, the more energy you use. Carbohydrate loading is comparable to hitting the pump one last time before embarking on a road trip, only a pasta dinner is much cheaper than filling your tank.
Italian Cuisine vs. Gels, Fruits, and Drinks.
Pasta and breads are complex carbohydrates. They are absorbed at a slower rate than their counter-parts simple carbohydrates (gels, sports drinks, fruit, etc). Your pasta and bread are broken down slower, which in turn allows for energy over longer duration events. For this reason, we look to top off our tank with Italian Cuisine a few days out, allowing for the molecule to broken down and stored in our reserves. Sports drinks, gels, and fruits, however, are simple carbohydrates. They are broken down rapidly and provide energy shortly thereafter. A quick shot of Gatorade can provide immediate energy and slow the breakdown of your energy reserves. Unfortunately, diffusion does not occur for half of the Gatorade that spills down your shirt.
How far out and how much?
There’s a ceiling to energy storage. Much like your gas tank, only so much energy can be stored. On the high end, research suggests beginning to supersaturate your carbohydrates 36-48 hours pre competition, while consuming up to 10g of carbohydrate for every kg of body weight. For example, weighing 158 lbs, I need to consume a maximum 710g carb/day to top off the tank, starting 36-48 hours prior to the gun. Ingesting further carbohydrates can actually have detrimental effects on performance. A side note: This can be a daunting task. Try to spread your consumption throughout the day over 5 hour periods (142g/hr).
For my US friends, convert your weight here: http://www.metric-conversions.org/weight/pounds-to-kilograms.htm
Will I gain weight?
You can expect to gain 1-3 pounds in your carb loading phase. Don’t fret. For every ounce of carbohydrate stored, you store roughly 3 ounces of water.
Skip the butter
When sopping up your red sauce, be sure to skip the butter. Fat-loading is not the goal here. Substitute a roll with butter for two rolls. A high-fat meal will not store glycogen.
The morning of the race
Emerging research is beginning to support to use of a high fat meal on race morning. I’m not talking about shoveling down burgers and fries, but items like peanut butter and toast. This new research indicates that the use of a high fat meal, roughly to be ingested 4 hours prior to start, will initiate the mobilization of fat for energy, conserving your glycogen reserves. You may also wish to sip a sports drink to refill any glycogen used throughout the night.
Remember, everyone is different. Use familiar foods and means to reach your carbohydrate goals. Don’t force it either; 10g of carbohydrates per kg of body weight is a lot—it’s a ceiling number not be exceeded. Spread your calories out throughout the day and avoid high fat foods prior to race day, as it can hinder your performance! Also, carb loading is for events lasting 60-90 minutes plus. Anything shorter doesn’t threaten your stored energy reserves.