Benefits of Carbohydrate During Exercise: A Closer Look at Energy Gels

[Source: East Coast Cycos newsletter, in Tri-Rudy newsletter, March 24, 2011]

Written by Holly Ortlund, M.S., Director of R&D, Carb-BOOM, Inc.


With so many different sport nutrition products on the market today it's difficult to sift through all the various claims and descriptions to find an energy product that best fits you and your active lifestyle. Protein bars, caffeine drinks, bee pollen…..the list goes on and on. Apart from the advantages these products promise, only one supplement, carbohydrate, has earned global acceptance and a wealth of respect for its benefit to the athlete. Researchers in the field of sports nutrition have long identified carbohydrates as the key nutrient for improving endurance performance during exercise.

Fat is the largest source of fuel in the body. An average-sized 150 lb person with 15% body fat has a significant amount of energy stored as fat. If a person of this size did not ingest any food during exercise and if fat were the only fuel used during exercise, stored fat alone could support physical activity for almost 7 days! However, due to the slowness of fat mobilization and other limiting factors, fat as a fuel is not able to support exercise above a very moderate level (>60% VO2max). Most athletes, both recreational and professional, train at intensities higher than this, therefore a supply of fuel other than fat must be available to the body. This preferred energy source is carbohydrate.

Carbohydrate is found in the body in 2 main forms, glycogen and glucose. Glycogen is a highly branched molecule made up of multiple glucose units and is stored in muscle and liver cells. Glucose, the body's preferred energy source, is found in the blood. If we take the same average-sized person mentioned above, and if carbohydrate were the only fuel used during moderate exercise, carbohydrate stores would only support physical activity for about 2 hours! Because we have such limited stores in the body and carbohydrate is the best energy source during moderate to heavy exercise, it is imperative that carbohydrate be ingested before, during, and after exercise in order to perform at the highest levels possible.

For the past two decades, scientific research has continuously demonstrated that carbohydrate ingested during exercise can improve endurance performance. How does it work? During activity lasting longer than 60 minutes glycogen levels begin to diminish and there is a progressive shift from muscle glycogen over to blood glucose as the body's primary fuel source. When muscle glycogen levels are low the consumption of carbohydrate serves to maintain proper levels of blood glucose and delay the onset of fatigue. In addition to this mechanism, carbohydrate ingestion also exerts its benefits at higher intensities of exercise by delaying and/or preventing muscle glycogen depletion (otherwise known as glycogen sparing). So how much carbohydrate is appropriate in order to gain this advantage? It's recommended that 30-60 grams be consumed per hour during intense physical activity.

Now that you know a little more about the role of carbohydrate in exercise, how do you decide which product to use? There are 3 main categories of carbohydrate energy foods-- drinks, bars, and gels-- all of which are currently available to the consumer. First introduced in 1967, sports drinks were the first commercially obtainable source of carbohydrates marketed as 'energy' products. These were followed almost twenty years later in 1986 by the introduction of energy bars. It took nearly a decade longer (mid 90's) for the first energy gel to emerge.

A common question often posed concerning carbohydrate supplements is the effectiveness of energy gels versus sports drinks versus energy bars in relation to endurance performance. What works best? Like all foods, it usually ends up coming down to personal opinions and experience. Any form of carbohydrate if taken in the appropriate amount will help delay fatigue during prolonged exercise. It's important that you find out which type of carbohydrate works best with your body. Sport drinks, with their high simple sugar content, have been known to cause stomach problems in some people, yet are easily digested by others. A number of athletes choose energy bars as their carbohydrate source, while many others cite the difficulty in getting them down and the burdened requirement that lots of water needs be taken along with them. Because of these issues, scores of athletes are now turning to the cutting-edge nutrition of carbohydrate gels as their main energy source during training a! nd competition.

Carbohydrate gels initially gained their popularity in the sports world with marathon runners and tri-athletes, but are now the desired fuel in numerous other sports as well. Nowadays, gels are often seen strapped to bikes, shorts, and ski bibs, ready to be ripped off and sucked down when needed.

Weighing between 1-2 ounces, energy gels are commonly available in 'easy-tear' foil packets. Depending on the brand, they provide 100 - 110 calories per serving and between 24 - 28 grams of carbohydrate. Possessing a smooth consistency and a high percentage of complex carbohydrates, gels are popular among many sports enthusiasts due to their convenience and instant surge of energy.

Many athletes prefer gels over sports drinks and energy bars because gels provide a super concentrated dose of carbohydrate that is absorbed very easily into the bloodstream. They provide a steady and continuous delivery of energy during periods of peak performance. Additionally, gels are attractive because they are not "heavy on the stomach" and are unlikely to cause gastrointestinal distress. Each gel pack provides enough carbohydrate to supply about 30 minutes of energy during physical activity. They offer the athlete a palatable, super fast, and easily digested fuel supply.

As with any supplement taken during exercise, it's very important to stay properly hydrated. Water helps to replenish fluids lost from sweating and provides optimal absorption for the carbohydrates. Most companies recommend that roughly 8-10 ounces of water be consumed along with each gel packet.

In summary, carbohydrates provide the best and most readily-available source of energy for your body during intense training or competition and are vital for keeping your muscles and mind operating at peak performance. Whether you prefer carbohydrate gels, bars or drinks, all are widely available to the consumer and offer a ration of energy to help improve endurance performance during exercise. So the next time you're out pushing yourself to the next level don't forget to take along a stash of this essential nutrient-you'll be very glad you did.