- Supercompensation as a biochemical foundation for carbohydrate loading
In preparation for starting in important sporting competitions, particularly endurance events such as marathons, cycling, triathlons, CrossFit or MMA competitions, many athletes engage in carbohydrate loading.The aim is to obtain maximum glycogen accumulation in the muscles, which is the basic energy component of strenuous effort. The principle is simple – the more glycogen that’s accumulated, the longer one can go for. Once, this was known only to marathon runners and bodybuilders who wanted to get on stage with the full, grainy appearance of inflated muscles. Interestingly, this nutritional strategy is quite poorly described and most people know very little about it. In this article I will present several types of carbohydrate loading described by scientists and coaches, and we’ll look at the supplements that can be taken.
More and more amateurs are taking part in extreme events, such as marathons and triathlons. Recently, there has also been a big boom in Mixed Martial Arts and there are now many more MMA events in Poland. A nutritional strategy called carbohydrate loading, based on the well-known supercompensation phenomenon, may be helpful during such intense exercise. Supercompensation describes an increase in the body’s efficiency, under properly selected training conditions, combined with appropriate regeneration in the form of sleep and selection of nutritional components from food and dietary supplements. It’s relevant to all aspects of an athlete’s activities: bigger, stronger muscles, thicker bones, improved oxygen threshold, more glycogen reserves stored in the muscles – these are all positive effects of well-planned training and adaptive characteristics acquired through proper dietary planning. But here, we are most interested in glycogen supercompensation, which occurs with optimally-performed training and subsequent relaxation. (Good rest and a period of nutritional well-being are as important here as the training itself). The duration of breaks between sessions and the occurrence of the supercompensation phenomenon depends on the type of activity during a session. The nature and intensity of loads have a huge impact on what is ‘optimal’ and when supercompensation will occur – the duration of the rest period can vary from 8 hours to as much as 72 hours. This also applies to carbohydrate loading, so in some disciplines they are shorter periods, lasting less than 12 hours, and in others longer – even up to 5 days.
The earliest references to the practice date back to the late 1960s. The first study of this phenomenon was conducted by a Swedish physiologist, Gunvar Ahlborg, following an earlier discovery that there is a positive relationship between the amount of glycogen stored in the body and muscle endurance. Researchers and runners had already observed that consuming meals rich in carbohydrates the day before prolonged their exercise time and increased their durability and ability to exercise, but no one knew why exactly. Ahlborg then showed the close relationship between stamina and glycogen reserves. He also discovered that the muscles and liver are able to store incredible amounts of glycogen, and that high carbohydrate intake preceded complete burnout of those reserves. We can see then, that the most obvious solution is to eat very small amounts of carbohydrates. But other scientists thought differently, and looked at athletes engaging in intense exercise. They saw that stress associated with significant burnout of glycogen reserves activates an adaptive response, as a consequence of which the body reduces carbohydrates from adipose tissue and deposits them as increased amounts of glycogen in the liver and muscles. Ahlborg described this phenomenon as glycogen supercompensation.
Armed with this knowledge he was able to create a method for loading up on carbohydrates that was more refined than before, which consisted more or less of eating a giant bowl of spaghetti. The researcher came up with the idea of a 7-day carbohydrate loading plan, in which intensive exercise was introduced after 3-4 days of very low-carbohydrate content (10% of daily caloric intake). This phase was followed by 3-4 days of extremely high carbohydrate supply (90% of demand). Athletes using this method were able to almost double their glycogen reserves and displayed much greater capacity to exercise, lasting longer than 90 minutes – a good amount of time for any such strenuous exertion. Following the publication of these results, athletes all over the world began to use Ahlborg’s strategy to extend their training to 90 minutes and beyond. Even though the plan worked perfectly, it still had some drawbacks. Firstly, many athletes did not enjoy the prospect of making an exhausting effort a week before competing. Secondly, maintaining energy intake of 10% carbohydrates for 3-4 days came with a few unpleasant consequences, including drowsiness, irritability, loss of concentration and increased susceptibility to illness. Eventually, many runners and other athletes decided it wasn’t worth the effort.
Happily, later research showed that glycogen reserves could be significantly increased without the need to first use them all up. Instead, athletes were required to follow a diet consisting of 55-60% carbohydrates for three days before the start, increasing to 70% in the last three days, including breakfast the morning of the event or start of training, etc. As for normal exercising, one more recent method suggests one long workout (without becoming exhausting) a week before the start, and then increasingly shorter sessions throughout the week before. This solution is simple, is not exhausting, and just works.
It should be remembered that an increase in carbohydrate intake should not be made by increasing total caloric intake, but rather by reducing the dose of fat and protein in an amount that is equal to or slightly exceeds the amount of added carbohydrates. Combining a smaller amount of training with more calorific intake causes weight gain, which will only slow you down. Also, remember that every gram of carbohydrate is associated with 2.7 g of water, which means that many athletes begins to feel heavy three days before carbohydrate loading. Although the feeling passes long before the end of competition, it can still be a problem.
A more friendly carbohydrate loading strategy was developed in 2002 by researchers at the University of Western Australia, which combines the exhaustion and the loading in the same day. The creators of this innovative method assumed that a single intense training session produces a very high demand for glycogen re-synthesis in both fast- and slow-twitch muscle fibres. They put forward the hypothesis that when following this kind of training, large carbohydrate intake can cause high levels re-synthesised glycogen without too much effort. In an experiment, the researchers asked athletes to perform short, high-intensity exercise consisting of two and a half minutes running at 130% VO2max, followed by a 30-second sprint. Over the next 24 hours, the athletes consumed 12 g of carbohydrate per kilogram of lean body mass. This resulted in a 90% increase in muscle glycogen content.
Runners were very pleased with the results. Performing only a few minutes of highly intensive training on the day before the competition does not sabotage their performance the next day, and doesn’t affect their overall fatigue level. In addition, it stimulates the desired carbohydrate absorption effect like a sponge, as in the Ahlborg loading strategy. This also allows athletes to follow their normal diet until the day before the competition, and only then load up with carbohydrates.
This new carbohydrate loading strategy developed by the University of Western Australia, works best when preceded by proper training, which means reducing training for several days in order to regenerate the body. In fact, a few days of reduced-intensity exercise combined with a normal diet (about 55% carbohydrates) will result in a significant increase in stored glycogen levels, even before loading. When we work out very hard almost every day, using a normal diet, the body does not get the opportunity to fully supplement its glycogen reserves, because another effort will again reduce its reserves. Only after 48 hours of very light exercise or complete rest is the total glycogen level fully levelled. And then, to achieve glycogen supercompensation, it would be a good time to apply the Western Australia loading strategy.
Carbohydrates are the most important fuel for the body when performing exercise above 65% of maximum intensity. Their sources are fairly broad and include glycogen, glucose circulating in the blood, liver glycogen and glucose produced in the liver with the other sources in a process called gluconeogenesis. Exhausting training and inadequate carbohydrate intake cause a gradual reduction of glycogen reserves in the muscles and liver, which weakens one’s capacity and increases the risk of injury. Eating meals rich in carbohydrates in the days before the competition or important workouts increases the glycogen reserves in the muscles and liver to levels higher than normal – this particular type of supercompensation is called glycogen supercompensation. Dr. Darlene Sedlock from Purdue University in Indiana presented practical suggestions to include carbohydrate loading into training programs. This proves itself best during endurance exercise lasting longer than 90 minutes, but can be also useful for bodybuilders doing prolonged intense weightlifting and aerobic workouts, as well as for MMA competitors. Having meals that are rich in carbohydrates increases glycogen reserves for up to five days. Even a single meal with a large dose of carbohydrates eaten on the day of competition increases its level, and food rich in simple or complex carbs is equally effective in loading.
Although I have previously described all of the known, proven carbohydrate loading strategies, it would be helpful to simplify and summarise them again. Choosing a particular strategy will depend on the discipline and its specifics, for example, whether we have to maintain our weight until the day before our event. Below you will find three carbohydrate loading solutions.
Using this method, do your last hard training 3 weeks before the competition. In the second week, begin to gradually reduce the intensity of your exercise. During this time, don’t eat meals with huge amounts of calories from carbohydrates, because the reduced exercise intensity means the body doesn’t require much. However, we need to provide calories in an amount that is typical for endurance exercise, ranging from 6-10 g per kilogram of body weight, while reducing the fat intake. Your muscles will use this additional supply of carbohydrates for the formation of glycogen reserves, as they will not be used in intensive training sessions. Under normal conditions, the body is able to accumulate glycogen equal to 80-120 mmol/kg. When this method is implemented perfectly, it allows almost double its reserves in the muscles, to about 200 mmol/kg.
In this method, the glycogen burning phase takes place six days before the competition. This training should affect mainly those muscle groups that will make the effort – often, however, all your muscles will be used. For example, if you start in a marathon, perform several sprint series as this will help you to burn glycogen in the target tissue. For the next three days, keep to your normal diet (6-10 grams of carbohydrate per kilogram of body weight), combining it with a decrease in training intensity. For the last 3 days, plan only for warm-ups or relax completely, while maintaining a high carbohydrate diet (10-12 g/kg body weight) containing very little fat.
This method doesn’t plan for tapering in the weeks before the start in competitions. It’s a great method for athletes who cannot afford to reduce their training intensity, who are due to compete in several competitions in a row, or who have a poor physical and mental tolerance to tapering. Regardless of the reasons, it is possible to achieve similar glycogen reserves by applying the 24 hrs method. To this end, an athlete will have to do a workout to burn-off glycogen reserves a day before the start. Immediately afterwards, they should consume 10-12 grams of carbohydrate per kilogram of body weight until the last meal before the competition – for example, breakfast. Thus, an athlete weighing 70 kg within 24 hours will deliver about 750 g of carbohydrate (3000 kcal). To do so, they will have to significantly lower their fat and protein intake, up to 10% of all calories.
While in endurance sports the carbohydrate loading described above can be justified, in several other disciplines it has a less obvious application. Below you will find related descriptions of relevant carbohydrate loading in bodybuilding and Mixed Martial Arts.
The aim of carbohydrate withdrawal followed by carbohydrate loading is to achieve maximally bulky muscles and improve their definition in relation to the greater pressure on the skin. Keep in mind that carbohydrates attract water – one gram of carbs binds 2.7 g of water. Since nearly 70% of the muscle mass is water, more glycogen, and more water means fuller muscles. And when combined with a temporary reduction of subcutaneous water by manipulating the minerals, the muscles look bigger, harder and better sculpted. However the very carbohydrate withdrawal and loading phase is slightly different as it mainly aims to obtain a good silhouette without building the energy base to maintain efficiency. Observation of your own body, its intuitive examination for insulin sensitivity and manipulation with minerals is very important here. It is believed that the carbohydrate withdrawal phase should last for a few days of the first half of the last preparatory week preceding the competition. However, you should not avoid carbs completely in your menu. Due to the general reduction in carbohydrates and calories consumption, and by introducing aerobic training session, the glycogen reserve levels at this stage are usually relatively low anyway. Getting to zero glycogen, even for a few days, may have strong catabolic effects under these conditions. Caloric shortages should be supplemented with protein or fat, otherwise there is a high probability that you will lose valuable muscle tissue. By consuming carbohydrates at specific times, you can remain in the burning fat and calories phase and ‘direct’ calories to muscle instead of fat tissue. To avoid the metabolic shock caused by a sudden 50% truncation of metabolic calorific intake (e.g. from 450 g to 225 g per day), the preparatory period is often divided into 34-week phases and one 3-week phase (the last week before the competition is usually a carbohydrate loading stage). In each phase, the carbohydrate intake is a bit smaller. I believe that with this approach, it is easier to maintain muscle tissue, as well as gradually but steadily keep burning fat. The following table illustrates a diet describing a carbohydrate withdrawal phase of up to 200 g in training days and 100 g on non-training days:
Weeks 16 – 12 (workout days)
First meal: 75 g
Pre-workout meal: 25 g
Meal during the workout: 25 g
Meal directly after workout: 75 g
Total: 200 g
Weeks 16 – 12 (days off)
First meal: 60 g
Second meal: 40 g
Total: 100 g
Weeks 12 – 8 (days off)
First meal: 50 g
Pre-workout meal: 25 g
Meal directly after workout: 75 g
Total: 150 g
Weeks 12-8 (days off)
First meal: 50 g
Second meal: 25 g
Total: 75 g
Weeks 8 – 4 (days off)
First meal: 40 g
Meal directly after workout: 60 g
Total: 100 g
Weeks 8 – 4 (days off)
First meal: 30 g
Second meal: 20 g
Total: 50 g
Weeks 4 – 1 (days off)
First meal: 20 g
Meal directly after workout: 30 g
Total: 50 g
Weeks 4 – 1 (days off)
First meal: 25 g
Total: 25 g
In the case of meals without carbohydrates, put the emphasis on large amounts of protein, essential fatty acids (mainly olive oil, fish oil, flaxseed oil, almonds, walnuts, natural peanut butter) and a moderate amount of green vegetables. Remember that unsaturated fatty acids better affect leptin – the satiety hormone – which is extremely important in such drastic food reductions. The type of carbohydrates you choose will depend on your insulin sensitivity, but usually the complex carbs-to-sugar ratio is 60:40.
For Mixed Martial Arts fighters, the carbohydrate loading phase is applied to restore efficiency and the athlete’s strength as well as to increase body weight during the weighing period for the fight, which is often 24-36 hours beforehand. This is a sufficient time to gain positive results with a properly planned water electrolytes and carbohydrates supercompensation phase. Usually, athletes have their everyday weight 10 kg higher than required for a fight. To reduce it, wise pre-start planning will subsequently include fat loss, muscle mass compression and disposal of water reserves. This latter is crucial because aggressive dehydration can significantly impair athlete endurance and motility during combat. Carbohydrate loading is necessary in this sport due to the fact that a common slimming method is using low-fibre with poor water absorption potential, such as protein and fat diet. After completely removing them from your diet, you still need to restore these reserve later. As you can see, in MMA, carbohydrate loading mostly includes recovery (to get maximally close) to your off-start-season weight and fill the muscles with energy for intense effort in the ring.
Many people are trying to supplement all carbohydrates only from ordinary food. Even with the use of juices, flavoured milk and other liquid carbohydrate sources, this may not be as effective. Using VITARGO ACTIVE FIRE or VITARGO ELECTRO ENERGY made by TREC you can accelerate the glycogen compensation process due to its unique properties – 70% of glycogen compensation level within the first 4 hours is faster than compared with other sources. However, it is not only the carbohydrate supplement that can help us. Arginine also has interesting properties because it increases glucose bioavailability in relation to muscle (see the ‘muscle pump’ article). Therefore, for the carbohydrates portion you can apply AAG MEGA HARDCORE, NITROBOLON or S.A.W. by TRECA. Use of supplements supporting insulin response sensitivity can also be helpful: HMB REVOLUTION FORMULA HMB, BCAA X-TANK (tyrosine inhibits serotonin synthesis in the brain, thus preventing the soporific effect of a large dose of carbohydrates), ANABOLIC BCAA SYSTEM LEUCINE FUSION – these are all amino acids that can help build glycogen reserves. Meal replacements make up the last group available as concentrated ingredients in the form of energy bars, for example BOOSTER.
Too many people follow ‘the more, the better’ strategy, which refers not only to the carbohydrate amounts but also the training. Remember that muscle glycogen is deposited – according to the supercompensation definition provided at the beginning of this article — during rest periods, when the body does not burn glucose during exercise. Therefore, training in the final preparation stage should be limited to a warm-up, and not be an exhausting training session, similar to those previously performed. The Australian Institute of Sport has collected the most common mistakes made when carbohydrate loading. These are:
No exercise taper. A carbohydrate loading phase must go hand in hand with tapering. Mandatory omission or a significant reduction in exercise intensity must be done for at least 1-4 days before the start of competition. Failure in this area can lead to glycogen supercompensation sabotage because you continue to burn the glycogen which you are supplementing with your diet.
Too-low carbohydrate intake during loading. It turns out that the majority of athletes have little idea of the amount of food required for proper carbohydrate loading. Working with a sports nutritionist and using tables of calories and carbohydrates can provide invaluable help.
Too much fibre intake. When eating such a large amount of carbohydrates, also have some of those considered to be less healthy, such as sugars contained in sweets, fruit juices, jams, honey and sports drinks. With a large supply of fibre you can suffer from gastrointestinal disorders, and you may suffer from diarrhoea at the start – this happens in 25% of marathon participants. In addition, eating only cereal-based products and potatoes can be a limitation as to the amount of supplied carbohydrates due to the large volume of food. It is almost impossible to take 8-10 grams of carbohydrate per kilogram of body weight only from starch sources. Most scientists recommended a 60:40 ratio of complex to simple carbohydrates.
Fear of gaining weight. Carbohydrate loading will cause weight gain of around 2-4 kilograms. This extra weight comes from the extra glycogen accumulated by muscle and water, which they bind to. Some athletes fear this effect and so sabotage proper conduct of carbohydrate loading phase.
Eating too much junk food. Athletes often use carbohydrate loading as an excuse to eat anything and everything in sight. Consuming too much fatty foods will significantly impair glycogen supercompensation. This may also result in an increased proportion of fat mass in the total body weight. It is very important is to stick to meals rich in carbohydrates that also have minimal fats and proteins. However, complete carbohydrate elimination also has a negative impact on loading and decreases insulin sensitivity. It is suggested to keep the proteins and lipids supply at 10% caloric content, while maintaining nearly 80% of the carbohydrates.
Does this nutritional strategy really work and is it an effective way to increase sports performance? The answer is yes. The carbohydrate loading mechanism was introduced in order to improve athletic performance. It can increase endurance by about 20% in the case of long-term workout, such as marathon running. This means that if, under normal conditions after running for 30 km you feel exhaustion, glycogen supercompensation resulting from properly planned carbohydrate loading may delay this feeling to up to 36 km, which is a very good result. For bodybuilders it means bigger, more clearly defined and fuller muscles, which can bring favourable scores from judges. For MMA fighters, it is one of the most important methods for getting very close to your opponent’s weight, and improving your mood and energy just before the fight. The effects of this phenomenon are not to be underestimated, and anyone who is serious about their sport should use carbohydrate loading before a big event.