The Significance of Carbohydrate Components in Post-Exercise Meals and Diet

Diets that restrict carbohydrate intake have been widely debated, particularly in relation to the cardiovascular system. Dr. Dena Bravata from Stanford University performed a meta-analysis of 94 dietary interventions published in scientific papers that examined the health effects of low-carb diets. The analysis showed a beneficial effect on markers of metabolic syndrome or a lack of effect. Although low-carb diets have been linked to reducing muscle mass, scientific research has shown something else. Studies conducted at the University of Connecticut in the USA in the field of exercise and aerobic exercise have shown that diets that provide muscle mass without weight gain and weight gain during exercise, in which carbohydrate intake does not exceed 50 g, have a better effect in many cases. However, the necessary condition is isocaloricity of the compared diets, which means that they should provide the same amount of kilocalories. Reducing the number of kilocalories without supplementing them with protein and fat intake will not allow for retention of dry body mass and optimization of sports results. Additionally, Dr. Volek has proven that reducing carbohydrate intake improves fat utilization processes during aerobic exercise, which can lead to improved endurance during endurance training.

The generally accepted view on the necessity of consuming carbohydrates, especially during the training period, is based on the belief in the crucial role of insulin in amino acid transport and the effect of this hormone on muscle mass. Carbohydrates are the most important component in stimulating insulin secretion, however, the supply of leucine, one of the main branched amino acids, is also a factor that stimulates the pancreas to release insulin. Consuming proteins rich in leucine, such as protein shakes, leads to a significant release of insulin. A high intake of carbohydrates is particularly recommended during the training period, as it is possible to quickly replenish glycogen stores in the muscles. However, this is not as obvious as it may seem. Complete depletion of carbohydrate stores in the muscles occurs mainly after long-lasting endurance training. Strength training does not require such a high use of glycogen as one might think. Studies carried out by Dr. Duncan Macdougall showed that a single series of exercises with dumbbells reduces glycogen consumption by 12%, while 3 series of this exercise lead to a consumption of 24%. Strength training leads to an average glycogen consumption of 40% in the trained muscle part. Although a post-training meal plays a key role in replenishing glycogen, assuming that carbohydrates are consumed in the remaining meals of the day, complete resynthesis of glycogen can be achieved within 8-24 hours after training.

Carbohydrates are commonly viewed as a macronutrient facilitating muscle mass buildup, however, all studies testing their efficacy indicate that they are unable to initiate the process of muscle protein synthesis when combined with protein. Dr. Aaron Staples of McMaster University conducted research showing that 25 g of protein has the same anabolic effect as a combination of 25 g protein and 50 g carbohydrate. Consuming carbohydrates leads to an increase in insulin levels, which allows for the maximization of muscle protein synthesis, however, as previously mentioned, sources of protein rich in leucine ensure sufficient insulin increase for the maximization of muscle protein synthesis and minimization of muscle protein degradation.