As any good trainer knows, peak fitness can only be maintained for a short period. If, as is often the case, you need this period to be extended over a particular range of days (or to fall on one particular day), you need to optimise your diet (as well as your training) to achieve this. The days immediately preceding the one in which you wish to be at peak form are usually dedicated to the disposal, through rest, of the fatigue waste accumulated during training. One of the aims of the physical unloading phase prior to peak form is to restore the energy stores consumed during training so that they can be fully utilised when most needed. Now, as previously explained, the energy sources from which, primarily, the body draws metabolic energy are carbohydrates and fats. With regard to the latter, however, there is (almost) always a large reserve available. Even athletes with extremely low percentages of fat mass possess enough fat to cope with the most varied athletic needs related to b-oxidation. As far as carbohydrates are concerned, on the other hand, reserves tend to deplete rather quickly, especially as they can only be stored (in the form of glycogen) in modest quantities. This is why, in the absence of countermeasures, it is quite common to arrive at the day when peak form is desired with glycogen stores at least partially depleted. It is known, in fact, that the body requires an intake of 5g of carbohydrates per kilo of body weight per day solely to conserve glycogen stores. It is therefore necessary to apply a strategy to avoid this situation, by adequately recharging liver and especially muscle glycogen stores just before the moment when maximum performance is required. A first indication comes from the work of Chryssantholoulos (2004), for whom taking 200g of carbohydrates three hours before the physical load increases the glycogen reserves that can be drawn on during exertion by 11%. However, a more significant energy recharge is possible by following slightly more complex methods.

The Ästrand method for glycogen supercompensation

  One of the best-known protocols for replenishing glycogen stores is the Ästrand method. This method was developed for endurance athletes. According to some authors it is ineffective for competitions lasting less than sixty minutes, while others suggest it for weightlifting competitions. The truth is probably somewhere in between: anyone who is about to perform aerobic or mixed aerobic/anaerobic performance will benefit from it. The Ästrand protocol lasts one week. It consists of two seamless phases:

• phase 1: depletion. During this phase, the aim is to completely deplete the glycogen reserves in such a way as to minimise insulin resistance by causing the GLUT-4 receptors to move from inside the cells to the membrane surface. On the one hand, the intake of carbohydrates in the diet must be reduced to a minimum (the classic protocol recommends 10% of the total calories of carbohydrate origin) and, on the other hand, glycogen stores, especially muscle stores, must be totally consumed by practising fairly intense training involving the muscle groups that will be stressed during the event for which one is preparing. This phase lasts two to four days.
• Phase 2: carbohydrate reloading. Once cellular sensitivity to insulin has been optimised, we can proceed with carbohydrate reloading. During this phase, training, if carried out, must be of moderate intensity, while the carbohydrate intake must be very high (the classic protocol recommends 80% to 90% of calories of carbohydrate origin). It is particularly important to maintain a normal protein intake. The carbohydrate-replenishment phase will cover the three days immediately preceding the event.

The attentive reader will probably have noticed a certain similarity with the alternation of carbohydrate loading and unloading suggested to those who opt for a low-carb diet. The Ästrand method, in fact, consists of a more drastic, but shorter version of the aforementioned protocol. It is also based on the same principles. Impossible to implement regularly (it is designed to prepare for a single event), unlike its more moderate counterpart, it is nevertheless more effective in saturating glycogen stores. Alternating days of unloading and reloading not only increases the quantity of glucose reserves, but also the efficiency of their metabolism.

Carbohydrate reloading with the Sherman/Costill method

  The Sherman/Costill method for saturating glycogen stores, unlike the Ästrand protocol, does not require alternating carbohydrate depletion and reloading. This protocol also lasts one week and simply consists of observing a diet in which 60-70% of the calories come from carbohydrates, halving the training load every two days, according to the more classic protocol, until arriving at complete discharge on the day immediately preceding the event for which one is preparing. It should be noted that taking 75% of daily calories in the form of carbohydrates for four days leads (in athletes specialising in endurance performance) to an increase in muscle glycogen stores of 23% in men and 17% in women. If, then, in the diet of the male athlete, calories are also increased by 34%, there is a further increase of 12% (for a remarkable total of 35%). To reconcile the total calorie intake, it is possible to make up the surplus, for the athlete who needs it, by taking fewer macronutrients in the days before the carbohydrate reload. Unfortunately, it appears that for women the calorie-boosting stratagem is not as fruitful as it is for men. However, an interesting way of applying the Sherman/Costill method is to regroup the bulk of the weekly carbohydrate intake in the last few days of the classic protocol, taking less on the preceding days. For example, if we assume that we have to take 2000kcal/day for seven days, the weekly calorie intake would be 14000. Now, if for the classic protocol you would have to consume 70% of these in the form of carbohydrates, you would have to consume 9800kcal of carbohydrate origin, i.e. 2450g of carbohydrates per week. If you want to consume 75% of your calories from carbohydrate sources in the last 4 days, you should consume 6000kcal of this origin during this period (2000kcal x 4 = 8000. 75% of 8000 is 6000), or 1500g of carbohydrates in 4 days. In order to maintain the weekly carbohydrate quota provided by the classic protocol (9800kcal), if 6000kcal is taken from carbohydrate sources in the last 4 days, then 3800kcal (950g of carbohydrates) will have to be taken in the first 3 days, i.e. about 63%. Of course this particular solution is only a hypothesis that may work for some and may not work for others. Some athletes may benefit more from a constant daily intake of carbohydrates. As usual, there is no golden rule that fits every athlete and every circumstance. Every athlete must learn to know himself and every coach must learn to know his athletes. The primary means of acquiring the required awareness is through experience and, if necessary, making mistakes. The Sherman/Costill method, compared to Ästrand, has the disadvantage that it does not allow the same ready utilisation of stored glucose. In other words, however saturated the glycogen stores may be, the body will draw on them more sparingly when it needs them than it would if the depletion phase had alternated with the reloading phase. Furthermore, as the high-carbohydrate regime lasts for seven days in a row, any metabolic state tending towards b-oxidation would be lost and, after the peak fitness period, would have to be restored as per the guidance given in the section on the ketogenic diet.

The short cycle for carbohydrate reloading

  Another way to do carbohydrate reloading is the Bussau method, which assumes the intake of 10g of high-GI carbohydrates per kilo of body weight in a 24-hour period. For example, an athlete weighing 70kg would have to consume 700g of high-GI carbohydrates in one day. According to Bussau (2002), doing so can double the level of glycogen stored in the muscles. It seems that prolonging the protocol for another 48 hours does not provide any further benefits. One could consider this method as a variant of the Sherman/Costill method in which there is an extremely short period for carbohydrate reloading on the one hand, but a very intense one on the other, since the magnitude of the carbohydrate load is very large (sometimes to such an extent that, with the carbohydrate intake alone, a considerable calorie surplus over the previously calculated requirement is implied). Athletes who do not have body weight problems could consider mixing it with the Sherman/Costill method or the Ästrand, making sure that the bulk of the carbohydrate load to be taken in is saved for the last day, by taking in less carbohydrate than in the protocol being followed on the previous days.