Nutritional opportunities in sports nutrition

　　Advanced nutritional strategies can accelerate recovery and help muscle growth

　　simply put

　　Nutrition timing refers to the concept that the timing and content of diet and surrounding training courses have a significant impact on improving muscle mass, body composition and function

　　The new vision of sports nutrition-not only edible, but also edible

　　Currently, overwhelming evidence supports the specific and strategic use of liquid formulations to provide accurate amounts of carbohydrates and protein to support recovery and training adaptability.

　　Background

　　Many metabolic reactions of exercise and training reflect the balance between decomposition and growth/synthesis. For example, at any given point in time, the amount of fuel stored in muscles for exercise (mainly in the form of carbohydrate molecules called glycogen) depends on the breakdown/use during exercise and the carbohydrate (CHO) diet or Recovery/synthesis of well-planned rehabilitation meals due to high-intensity exercise. Similarly, it is now believed that the growth of muscles in response to training depends on the individual's ability to optimize training and nutritional strategies, so the process that affects muscle growth (called muscle protein synthesis) exceeds the process that leads to muscle failure (called muscle protein degradation). In recent years,

　　These observations led to the concept of "nutrition opportunity" in sports nutrition. In short, the choice of nutritional time is not only related to what to eat, but also to the time to eat, which also adds a layer of complexity to sports nutrition recommendations. The concept is that targeted and strategic control of nutritional intake can optimize the recovery process of muscle growth, fat burning/body composition and fuel storage before, during and after exercise.

　　"Window of Opportunity" after exercise

　　A key factor that explains why nutritional timing can more effectively achieve these adaptive changes (as opposed to only relying on nutritional strategies that solve the total daily intake) is the "window of opportunity" phenomenon after exercise. This is a short time (0-4 hours) after exercise, which can maximize the anabolism (growth) process in the body. This means that muscles that work hard during training or competition can absorb nutrients and (1) store them for future exercise (i.e. muscle glycogen), or (2) produce new muscle protein to repair damaged muscles and Help them grow. For example, by converting carbohydrate-containing foods into muscle glycogen, muscles can restore their fuel storage rates, 2, 3, 4, and 5.

　　The meaning of 　　 and the key point of nutrition timing is that providing nutrition to the body as soon as possible after exercise can optimize the recovery and activation of various processes (Figure 1). In fact, starting the recovery process by shaking before and/or during exercise may bring more benefits to the muscle growth process3,6.

　　Composition and formula of recycled powder in nutritious diet

　　Many studies have studied the composition of the diet after exercise and its effect on exercise recovery. Reviewing all of this is beyond the scope of this article. In short, in almost all cases, the best strategy to restore nutrition is to combine carbohydrates and protein and limit fat intake. Current research focuses on optimizing the proportion of these macronutrients. According to the latest consensus of the International Society of Sports Nutrition and the American College of Sports Medicine, the current consensus is that a ratio of CHO to protein of 31:1, 4 or 5:1 is the best choice for restoring CHO storage and muscle protein synthesis, respectively. This combination is so effective because CHO provides a source of glucose (sugar) in the blood to restore fuel storage, while protein provides a source of amino acids (the constituent components of protein). The synergy comes from the fact that glucose and amino acids can stimulate the production of insulin. Insulin plays a very powerful role in anabolic hormones, stimulating muscle recovery and growth. The combination of high glycemic index CHO or sugar with a fast digestible protein or amino acid source is very important for a "perfect" recovery drink9.

　　Some studies support the view that the composition of the recycled powder is very important for adaptability. During the 54-day basic training period, nearly 400 U.S. Marine Corps recruits were recruited immediately after the training every day. People who received CHO protein supplementation had fewer muscle soreness and joint problems, fewer infections and medical treatments, and fewer fevers. Compared with people taking placebo or CHO, exhaustion can only supplement 10. Among men who received 14 weeks of training, 25 g of protein or CHO were combined immediately before and after each training, and only the proteome showed improved sin muscle size (15-25%) and performance (vertical jump) after training . These results are almost identical to the design of another 10-week training study, although in this study, the CHO group did increase muscle mass and strength changes in the larger protein group. Finally, another resistance training study (12 weeks) compared the effects of taking placebo, 38 grams of CHO, 6 grams of EAA or CHO (38 grams) and EAA (6 grams) combined supplements. Exercise while drinking. Although the amount of fat loss was similar in all groups, the lean body mass (ie, muscle) increase in the CHO EAA group was greater than the other three groups. In this case, using only CHO or EAA was better than placebo. CHO EAA supplements have a stronger ability to prevent muscle protein breakdown during the recovery process, which explains this effect.

　　Another important finding in nutrition is that a specific subset of amino acids is called branched chain amino acids (BCAA). In particular, BCAA leucine is mainly responsible for the protein's role in stimulating muscle growth during the recovery process14,15. These amino acids are described in more detail in our amino acid article, but it is worth noting that even as little as 6 grams of BCAA can effectively stimulate muscle growth during recovery.

　　The role of timing of nutrition in adaptation and recovery——documentary evidence

　　In order to restore muscle fuel reserves, a groundbreaking paper described the effect of delaying meals after 2 hours of exercise, because the glycogen synthesis rate within 2 hours after each meal is 45% lower than that of meals consumed immediately after a meal. In addition, when muscle glycogen was measured 4 hours after recovery, the total glycogen level of the immediate recovery meal was 35% higher than that of the delayed recovery meal. However, a similar paper extended these findings to measurements at the 8th and 24th hours of recovery and found that there was no difference in the recovery of fuel storage when the feed was delayed by 2 hours. In short, it is very important to avoid delays for athletes who exercise intensely for two days a day, or in a game where there are several games in a day. The adverse effects of delayed eating after exercise are also manifested in the process of muscle growth. For example, eating immediately after exercise can cause muscle protein synthesis during the recovery process to be three times faster than eating after a 3-hour delay2. As mentioned above, drinking the CHO-amino acid combination immediately before and during exercise may add even more benefits, especially during the beginning of the muscle growth process3.

　　The focus of these two studies is on the process of recovering from exercise in a short period of time and only responding to one exercise. The following questions must be asked: Will these observations about the recovery process ultimately lead to a real increase in muscle mass? Improve training adaptability. In short, they will.

　　An early rodent study showed that rats fed immediately or 4 hours after each resistance exercise, rats fed immediately after 10 weeks of training had higher muscle mass (6%) and lower fat mass (24%). A few years later, this principle was embodied in humans for the first time. Elderly men who received 12 weeks of resistance training received 10 grams of protein, 7 grams of CHO, and 3 grams of fat supplements immediately or within 2 hours after each training session. Only in the immediate feeding group, the size of the quadriceps muscles increased, and the increase in leg strength was about 25% higher than that in the delayed feeding group. Finally, two groups of young men with matched diets and intake of the same CHO protein-creatine supplement received a 10-week resistance training intervention. The difference between the two groups is the time spent: one group takes supplements before and immediately after training, and the other group takes supplements in the morning and evening when there is no training. After 10 weeks of training, although the strength and muscle mass of the two groups have increased, the strength and muscle mass of the regular/supplemented regular supplement group 6 increased, and body fat decreased more.

　　In summary, research on nutritional time indicates that the maximum adaptation training may lie in the ability to maximize anabolic (growth and recovery) environment in the post-exercise period. This can be achieved through appropriate content (a mixture of CHO and protein) and timing (before, during and after training). It is possible that some changes in strength and muscle mass can still be obtained, but the magnitude of these changes may be less than the magnitude obtained by adopting an appropriate nutritional timing strategy1.