This is half the truth. The glucose requirement is well known, and is calculated on the minimum level constituted by the requirement of the central nervous system (about 120 g / day). Generally, it is stated that a not too active organism requires 7-8g of glucose per hour (0.1-0.12g / kg of body weight).
Then, we know that by neoglucogenesis (GNG) the liver is capable of synthesizing glucose, especially starting from neoglucogenic amino acids (such as leucine, isoleucine, valine, glutamine and arginine), from lactate and glycerol. However, this process has a limit and cannot be perpetuated.
It is also true that many tissues can also "work" by oxidizing other substrates (fatty acids, ketone bodies, branched amino acids), but this does not mean that they maintain the same efficiency; in fact, if on the one hand the organism can adapt to a lack of glucose, the total lack results in the accumulation of ketone bodies with a toxic effect. Therefore, in the long term, the lack of dietary carbohydrates is not compatible neither with good health, nor with muscle and metabolic efficiency, much less with the survival of the individual.
During a short-term caloric / glucose "restriction", the blood glucose level is maintained stable (65-80 mg / dl) through GNG, under stimulation of glucagon (insulin antagonist), whose release is increased by the drop in blood sugar and insulin. However, referring to an athlete, it can be noted that fatigue during training is proportional to the depletion of muscle glycogen. This is why low carb diets are not suitable for those who practice sports, especially those of the prolonged aerobic type. In a sedentary individual, on the other hand, whose amount of muscle glycogen is around 80-110 mmol / kg - and is less than the 110-130 mmol / kg of an athlete - the lack of carbohydrates is better tolerated; this is because the muscle glycogen is recruited only for the metabolism of the local tissue, while the glycaemia must comply with the liver.
During a glucose restriction, the amount of muscle glycogen is lowered to about 70 mmol / kg, and at this threshold the oxidation of fats increases (already in the first 12 hours), both at rest and during training. When the amount of glycogen is lowered to about 40 mmol / kg the athletic performance of a sportsman is affected. Reaching the threshold of 15-25 mmol / kg comes fatigue.
without taking carbohydrates? If so, in what quantity?After a lactacid anaerobic training session, about 20% of the lactate produced is used for the resynthesis of glucose and subsequently of glycogen. The conversion from lactate to glycogen is approximately 1 mmol of glucose for every 2 mmol of lactate. If we consider a potential of only 20% in the conversion from lactic acid to glycogen we can understand that the glycogen resynthesis in the post-workout fasting is really negligible and would not allow a second training session or in any case to maintain a greater volume of training. This, of course, is of less interest to a bodybuilder whose workouts last an average of 1 hour - in which effort takes only 25-30% of the time - and are followed by a long rest, but it is essential for athletes from other sports.
average during a weight training session, with an intensity of about 70%, is about 7.8 mmol / kg / set (at 70% of maximum intensity it is about 6 or 8 repetitions per set). Or 1.3 mmol / kg / rep or 0.35 mmol / kg / second. Of course, the higher the intensity, the greater the consumption of glycogen, but this affects less than in an aerobic activity. By raising the intensity it is necessary to lower the volume of the session and vice versa.
Let's take a practical example, taking into consideration a daily training schedule consisting of 6 series for 4 different exercises at 70% of 1RM (100% of 1RM means the "use of a weight that allows you to do a single" , maximum, repetition):
- 7.8 x 6 sets = 46.8 mmol of glycogen consumed during a single exercise
- 46.8 x 4 exercises = 187.2 mmol of glycogen consumed during the session.
Recruiting on average about 2 kg of muscle tissue per exercise:
- 187.2 x 2 = 374.4 mmol of glycogen consumed during the session (rounded to 375 mmol).
- If 1.0 g of dietary carbohydrates produces about 5.56 mmol of glucose-glycogen, making the mmol consumed divided by 5.56 (for example 375: 5.56) you get the carbohydrates needed for training (in this case 75 g) - 75 g of carbohydrates are contained, for example, in 200 g of white bread.
We could also say that the average consumption of glycogen during the "workout" is about 1.8-2.2 g x kg of lean mass.
To establish the right amount of carbohydrates (days of WO) it is therefore necessary to consider the empirical consumption of muscle glycogen during training, but also the metabolic demand of the nervous tissue (which, as we have said, corresponds to about 120 g / day).
- Staying on the example just made: 75 g + 120 g = 195 g
It is good to remember that the replenishment of glycogen stores is not instantaneous, so these carbohydrates cannot be taken only before training. Furthermore, by eating too many carbohydrates before the session, many suffer negatively the "increase in insulin", accusing exhaustion and difficulty. of concentration.
It might be a good compromise to limit to about 40% of the carbohydrates in the two pre-workout meals and the remaining 60% in the immediate post.
Read on: Antobolic Diet
