What is Carb Loading, and is it Bad?

This past week, my boyfriend and I went out of town for a few days. Up until then, I had been eating fairly healthy- maintaining a super low calorie diet consisting of mostly fresh fruits and veggies and low fat milk products/high protein. However, during the two to three days that we were away, I decided to ease up on my eating habits….a lot. The result? I almost immediately felt bloated and disgusting, although the comment was made that my muscles looked like they were popping out. My boyfriend, a former personal trainer, told me that when you deprive your body of carbohydrates and then suddenly load up on them, the result is that it makes your muscles “pop”. Apparently, my 3 day hiatus was spent carb-loading. Still confused?

What is “Carb Loading”

Carbohydrate loading, commonly known as “carb-loading,” is a strategy employed by endurance athletes as well as bodybuilders whereby a person will load up on carbohydrate-rich foods in order to maximize the storage of glycogen in the muscles. Doing this provides an extra energy reserve when energy expenditure is prolonged. This is often why you’ll hear about marathon runners having huge pasta dinners a few nights before the a race.

For bodybuilders, obviously, carb-loading is not done for endurance reasons. Rather, for them, carb-loading allows for a slow caloric increase prior to a bodybuilding competition. For example, one to two weeks prior to a competition and before beginning the gradual carb-loading program, a bodybuilder will typically be at his or her desired body fat percentage (which is already pretty low). At this point, the athlete’s carbohydrate and glycogen levels will also be at their lowest. The additional calories fill glycogen stores, thereby enhancing fullness and hardness of muscles from strict dieting. The physical result is that muscles look fuller, often giving an appearance of “popping out”.

Understanding the importance of the role that carbohydrates play in your diet as well as knowing how many carbs you should consume before, during and after competition/training is important to your overall health and athletic performance. According to HealthJournal:

Normal training diets should ideally be high in carbohydrate, low in fat and protein, so that the body is accustomed to taking in carbohydrates throughout the day. If your daily intake of carbohydrate is not at least 60 percent of the daily caloric intake, you may not be replenishing your liver and muscle glycogen stores and these levels will drop below normal and stay there. Not being able to train consistently on a day-to-day basis may be a sign of chronic glycogen depletion. 

To prevent chronic depletion of glycogen you need to consume approximately eight to nine grams of carbohydrate per kilogram of body weight on a daily basis. One gram of carbohydrate equals 4 kilocalories and a kilogram equals 2.2 pounds. This carbohydrate can be in the form of complex carbohydrates (breads, pasta, potatoes, etc.) or in the form of simple sugars (fruits, sweets, etc.).

Many athletes find it hard to eat such large quantities of carbohydrates. In these circumstances, a liquid, high-carbohydrate source such as Carbohydrate Sports Drinks is convenient. If mixed to the manufacturer’s instructions, they contain between 20 to 25 percent carbohydrate, ideally in the form of glucose polymers, which, unlike fructose, will not draw excess water into the gut. This concentration is about 3 to 4 times that found in so-called commercial sports drinks. 

Carb-loading also means that you should reduce your training intensity in order to allow your muscles time to rest and become completely loaded with glycogen. This is especially important for endurance athletes who will want to start their races or training with as much glycogen as possible. Additionally, you should never neglect to hydrate yourself during your training as well as after your training. It is recommended that you should drink 8 ounces of water (or an energy drink) ever 15 to 20 minutes, whether you are thirsty or not. During exercise, your body loses fluid as well as carbohydrates, and drinking water will help to replace some of these fluids.

*For runners (like myself) who go for runs ranging from 7 miles to 13 miles, it is often not practical or comfortable to carry a bottle of water. This is where it helps to know where water fountains are located; otherwise, you can simply fill up a water bottle and strategically place it on your running route ahead of time. If all else fails, pack a bottle of water with plenty of ice and leave it in your car for immediate consumption after you finish your run.

A Brief History of Carb-Loading [source]

The practice of carb-loading dates back to the late 1960s. The first carb-loading protocol was developed by a Swedish physiologist named Gunvar Ahlborg after he discovered a positive relationship between the amount of glycogen (carbs stored in the muscles and liver) in the body and endurance performance.

Scientists and runners had already known for some time that eating a high-carbohydrate diet in the days preceding a long race enhances performance, but no one knew exactly why until Ahlborg’s team zeroed in on the glycogen connection.

Subsequently, Ahlborg discovered that the muscles and liver are able to store above-normal amounts of glycogen when high levels of carbohydrate consumption are preceded by severe glycogen depletion. The most obvious way to deplete the muscles of glycogen is to eat extremely small amounts of carbohydrate. A second way is to engage in exhaustive exercise.

The Ahlborg Carb-Loading Method:

  • Perform an exhaustive workout one week prior to a long race (90+ minutes).
  • Consume a low-carb diet (10%) for the next 3-4 days while training lightly.
  • Consume a high-carb diet (90%) the next 3-4 days while continuing to train lightly.

For more information on the evolving art of carbo-loading, click here.

Where are Carbohydrates Found?

Carbohydrates can be found mostly in grains, dairy products, fruits, veggies and legumes (beans, peas, etc.). They are also found in sugar and sweets (which should be consumed sparingly). Carbs are what fuel your body’s energy. During digestion, your body converts carbs into sugar. This sugar then enters your bloodstream, where it is transferred to individual cells in order to provide energy. The leftover sugar is stored in your liver and muscles as glycogen.

Glycogen defined: Glycogen is the way in which the body stores glucose for later use. It is a large molecule produced in the liver, although it is also stored in the muscle and fat cells. After carbs are ingested, more glycogen is produced and then released as blood glucose levels fall. Low-carb diets initially deplete glycogen storage (as do any weight loss diets), and since glycogen molecules have quite a bit of water attached to them, people usually see a significant loss of “water weight” at the beginning of their diets. This should not be confused with “fat loss” however.

Lack of activity destroys the good condition of every human being, while movement and methodical physical exercise save it and preserve it. ~Plato

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