Also known as carb loading or carbo-loading. It happens when a few days prior to an event an athlete increases his/her carbohydrate intake in order to maximize the amount of glycogen stored in the muscles and liver.
Any individual that trains hard must understand how important the role carbohydrates (CHO) play before, during, and after a workout/competition. It is important to know how much CHO to consume at these given times. The average athlete can store between 1500 - 2000 kilocalories (kcal) of CHO. When the CHO stores are depleted, the athlete can experience heavy and/or tired muscles, decreased performance, or overall fatigue.
WHAT IS A CHO?
A CHO is, in a nutshell, a sugar molecule. When combined together they form fruits, vegetables, breads, grains, sugar, etc. They are broken down in the body through the act of digestion so they can be used as energy (fuel) for muscles and, most importantly, the brain. They are broken down into 2 categories:
Simple CHO
They are small molecules that require little to no digestion. Since they are small, they can be easily digested so assimilation into the bloodstream can happen at an accelerated rate in order to provide a quick surge of energy. The following are some types of sugars:
- Fructose: fruit
- Lactose: milk and milk products
- Dextrose/glucose: syrups
- Sucrose: refined sugars like table sugar, candy, soft drinks
Complex CHO
They are much larger molecules and are often found in starchy foods (beans, potatoes, rice, pasta, etc.) and vegetables. The body must break down the complex CHO into more simple units. Some complex CHO are absorbed more quickly than simple CHO (i.e. white bread, snack crackers) because they contain very little nutrition making it easier for the body to break it down and assimilate. Not only do complex CHO provide glucose for energy, the majority of them contain essential minerals, vitamins, and fiber. The following are examples of complex CHO that are good when CHO loading:
- crackers , wheat, grits, oatmeal, cornmeal, yam, bagel, beans, peas, potatoes, bran, wheat germ, corn, bread, rice, pasta
Glycogen
Glycogen is only found in the body. It cannot be ingested. When a CHO is ingested, the body uses as much of the CHO for energy. If there is any CHO leftover, the body converts it to glycogen which is then stored in muscles, liver, and fatty tissue. When blood sugar levels drop during an event, the body releases the stored glycogen from the liver into the blood in order to provide fuel for the muscles and, ultimately, the brain.
HIGH-CHO DIET
Research has found that normal training diets should be high in CHO, at least 60% of the daily caloric intake. But consuming these amount of CHO are only beneficial to the athlete that is training for or competing in events that are greater than 90 minutes in duration. In order to prevent CHO depletion, the athlete should consume 8-9g/kg of body weight daily.
CHO-LOADING
The goal of CHO loading is to prevent the onset of fatigue during endurance events. It benefits the athlete that is involved in endurance events (i.e. marathons, triathlons, swimming, etc.). Sports nutritionist have found that CHO loading should start 2-3 days prior to the event. The CHO intake should be increased to 9-10g/kg, or 70% of daily dietary intake. When the time arrives to increase CHO intake, the intensity of training must be decreased and no training must take place one day prior to the event. By decreasing the training load, the muscles are able to become fully saturated with glycogen. High CHO supplement drinks can assist in reaching the goals of CHO consumption.
Pre-Event
Meals that are consumed 2-3 hours before a competition help to ensure the muscles and liver are fully saturated with glycogen. In the last minutes before the start of the event, consuming a 10-12 oz. sports drink (i.e. Gatorade) or gel pack will help top up any glycogen reserves that may have been used up by warming-up.
During Exercise
Any food and drinks that are high in CHO should not be consumed during the event. Regardless if they are simple or complex CHO, they will sit in the stomach longer due to delayed emptying and decreased blood flow to the stomach. This can lead to stomach cramps and even nausea and vomiting. Sports drinks are advisable. It is recommended that an athlete drink 8 oz. of an energy drink every 15-20 minutes regardless if he/she is thirsty or not.
Post-Event
A lot of research has been conducted with regards to post-exercise nutrition. Dr. John Ivy of the University of Texas recommends that an athlete consume 1g/kg of bodyweight of CHO in the initial 30 minutes and then consume 1 g/kg every 2 hours for the next 4-6 hours post event. As well, protein is very important for the repair of damaged muscle fibers. A high quality protein (i.e. whey protein) is recommended. The ratio of CHO to protein is 4:1.
RISKS OF CHO LOADING
There are some risks involved when CHO loading. CHO loading is not intended for every athlete. Some of the risks associated are, but not limited to:
- Weight gain: usually most of the weight is extra water because for every gram of glycogen stored in the body, there is 3 grams of water retained. Some of the gain can come from excess storage of glycogen as fat in fatty tissue.
- Digestive discomfort: loading up on complex CHO such as broccoli, beans, and bran, for example, can cause bloating, gassy cramps, and loose stools. The aforementioned examples are high in fiber.
- Blood sugar fluctuations: when CHO are absorbed into the bloodstream, insulin is released from the pancreas in order to transport the glucose to the required areas. Too much insulin can cause hypoglycemia (low blood sugar) which could lead to a myriad of problems. With the increase in insulin production, fat mobilization for energy is interfered with which disrupts other hormonal balances leading to hypertension, high blood cholesterol, and higher triglyceride levels.
In conclusion, carb loading for CrossFitters is pretty much a mute point. The majority of workouts are completed in a relatively quick fashion. Since the workouts are constantly varied, it is pretty much impossible to carb load because there is not ample time to do so. Unless, the workout is planned like the Fight Gone Bad Challenge or CrossFit Games/Challenges.
References
http://www.bodyandfitness.com/Information/Fitness/carb1.htm
http://www.centralhome.com/ballroomcountry/optimal_nutrition.htm
http://www.centralhome.com/ballroomcountry/carbohydrate-loading.htm
http://www.indoorclimbing.com/carbohydrate-loading.html
http://www.mayoclinic.com/health/carbohydrate-loading/MY00223
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