dE^SiRE
wiesz co, ja juz od paru miesiecy jestem na niskoweglowodanowej diecie, i jest calkiem niezla 
oto art:
BEFORE
Pre-workout nutritional strategies are based on providing alternative energy substrates (mainly carbohydrate) to preserve energy stores, and taking advantage of increased blood flow to muscle tissue.
Carbohydrates
High intensity exercise places great demand on glycogen stores. Glycogen is the sugar stored in the liver and muscles. Because high intensity exercise burns energy at such a high rate, the body is unable to supply sufficient oxygen to be able to use fat for fuel. Instead, it must use sugar both stored in the muscle and brought in from the blood.
Consuming simple sugars right before training can reduce the amount of glycogen used during exercise. This can prolong performance. More importantly, higher blood sugar and insulin levels appear to create a hormonal milieu favorable to anabolism (growth).
During exercise, cortisol accelerates lipolysis, ketogenesis, and proteolysis (protein breakdown). This happens in order to provide additional fuel substrates for continued exercise. The effects of cortisol may also be necessary to provide an amino acid pool from which the muscle can rebuild new contractile proteins if there are insufficient amino acids delivered from the blood. This ensures that some degree of adaptation can occur regardless of the availability of dietary protein. Over time however, if this process is not balanced with additional dietary protein, the net effect will be only maintenance or even a decrease in functional muscle tissue, as is evident during periods of starvation or prolonged dieting. Fortunately, there is only a non-significant rise in cortisol levels when carbohydrates were consumed during exercise. (Tarpenning, 1998) The net effect is a more rapid increase in the cross sectional area of the muscle fibers with the greatest effect seen in type-II fibers.
This may be a less expensive option for those who were thinking of using phosphatidylserine. In this case, carbohydrate administration appears to down regulate the hypothalamic-pituitary-adrenal axis, probably through insulin or perhaps through the presence of carbohydrate itself. This would, in effect, greatly reduce the body's catabolic response to exercise stress. All good news for bodybuilders.
"Protein
Another pre-workout strategy involves taking advantage of increased blood flow to working muscles. Because the availability of amino acids is often the limiting factor for protein synthesis, a pre-workout protein meal will enhance the delivery of amino acids to muscle tissue. Research has demonstrated the effectiveness of a pre-workout protein drink.
Delivery of amino acids has been shown to be significantly greater during the exercise bout when consumed pre-workout than after exercise (Tipton, 2001). There is also a significant difference in amino acid delivery in the 1st hour after exercise, with the pre-exercise protein drink providing a significant advantage. Net amino acid uptake across the muscle is twice as high with a pre-workout protein drink as compared to consuming it after. Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, was significantly higher when amino acids were taken pre-workout. These results indicate that the response of net muscle protein synthesis to consumption of a protein solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.
post
Protein
Protein is another critical nutrient post-exercise. Protein is essential to post exercise anabolism. Protein provides amino acids that are used to rebuild damaged tissues as well as provide enzymes and carrier proteins necessary for adaptation to exercise. Without protein, which supplies essential amino acids for endogenous protein synthesis, the body's ability to adapt to exercise is greatly diminished.
Studies have shown a 12 to 14 day period after the onset of an unaccustomed exercise program, in which nitrogen balance, the ratio of protein intake to protein loss, is negative (Butterfield 1987). Any study looking at protein needs and exercise must take this into account. Nitrogen balance during this period appears to be insensitive to total caloric intake, but can be improved with a high protein intake if adequate calories are supplied (Gontzea 1975). Even though additional protein intake will prevent nitrogen balance from becoming negative, it will still fall despite high protein intake during the first two weeks of exercise.
Muscle specific messenger RNA (mRNA) produced subsequent to training has a half-life of only 4-5 hours. It is so short because mRNA has no "quality control" mechanism built into the coding. By keeping the half-life short, any errors in the sequence won't be able to produce enough defective proteins to do irreparable damage to the cell or organism. This also allows tight control of protein metabolism.
The timing of protein intake is important. If the anabolic stimulus from exercise is to be maximized, a steady flow of amino acids must bathe the muscle while mRNA content is high. It should be no surprise that the optimum time for protein intake after your workout is relatively brief compared to frequency of training a particular muscle. Muscle protein synthetic rate (MPS) is elevated in humans by up to 50% at about 4 hours following a bout of heavy resistance training, and by 109% at 24 hours following training. A study done by Macdougall (MacDougall et al 1995) further examined the time course for elevated muscle protein synthesis by examining its rate at 36 hrs following a bout of heavy resistance training. Six healthy young men performed 12 sets of 6- to 12-RM elbow flexion exercises with one arm while the opposite arm served as a control. MPS was calculated from the in vivo rate of incorporation of L-[1,2-13C2] leucine into biceps brachii of both arms over 11 hours. At an average time of 36 hours post-exercise, MPS in the exercised arm had returned to within 14% of the control arm value, the difference being nonsignificant. The following conclusions can be drawn from this study, following a bout of heavy resistance training, muscle protein synthetic rate increases rapidly, is more than double at 24 hours, and then declines rapidly so that at 36 hours it has almost returned to baseline.
Current recommendations for total protein intake for athletes is between 1.6-1.8 grams per kilogram body weight, depending on who you read, however, it is not uncommon for bodybuilders to consume in excess of 2 grams per kg of body weight with no ill effects. It should be remembered that the body does not have the capacity to effectively store amino acids. Protein should be eaten at least every 3-4 hours. The evening meal should contain slowly digesting protein that will allow a steady release of amino acids into your system well into the night. Dinner is a perfect time for steak or other meat dishes."
"It's about synergy
As mentioned earlier, macronutrient intake modulates post-exercise protein synthesis in ways that are just beginning to be understood. Yes, protein is required to supply essential amino acids for protein synthesis, but what is the mechanism by which protein is controlling this process? Also, are carbohydrates and fats needed only for fuel replacement, or do they play an "interactive" role in post exercise protein synthesis? Recent research has shed light on these questions.
Researchers from the Division of Nutritional Sciences at the University of Illinois examined the effect of post exercise meal composition on protein synthesis. To do this, they looked specifically at the activity of specific proteins known to regulate protein synthesis at the translational level.
Initiation of translation (the binding of mRNA to the ribosomal pre-initiation complex) requires group 4 eukaryotic initiation factors (eIFs). These initiation factors interact with the mRNA in such a way that makes translation (the construction of new proteins from the mRNA strand) possible. Two eIFs, called eIF4A and eIF4B, act in concert to unwind the mRNA strand. Another one called eIF4E binds to what is called the "cap region" and is important for controlling which mRNA strands are translated and also for stabilization of the mRNA strand. Finally, eIF4G is a large polypeptide that acts as a scaffold or framework around which all of these initiation factors and the mRNA and ribosome can be kept in place and proper orientation for translation.
The researchers in this study looked at the association of the mRNA cap binding protein eukaryotic initiation factor-4-E (eIF4E) with the translational inhibitor 4E-eukaryotic initiation factor binding protein-1 (4E-BP1) in the acute modulation of skeletal muscle protein synthesis during recovery from exercise. Fasting male rats were run on a treadmill for 2 h at 26 m/min and were fed immediately after exercise with saline, a carbohydrate-only meal, or a nutritionally complete meal using Ensure Powder (54.5% carbohydrate, 14% protein, and 31.5% fat). Exercised animals and non-exercised controls were studied 1 h post-exercise.
Muscle protein synthesis decreased 26% after exercise and was associated with a fourfold increase in the amount of eIF4E present in the inactive eIF4E.4E-BP1 complex and a concomitant 71% decrease in the association of eIF4E with eIF4G. Refeeding the complete meal, but not the carbohydrate meal, increased muscle protein synthesis equal to controls, despite similar plasma concentrations of insulin. Additionally, eIF4E.4E-BP1 association was inversely related and eIF4E.eIF4G association was positively correlated to muscle protein synthesis. This study demonstrates that recovery of muscle protein synthesis after exercise is related to the availability of eIF4E for 48S ribosomal complex formation, and post-exercise meal composition influences recovery via modulation of translation initiation.
The results of this study tell us a few things:
1. Insulin (via carbohydrate intake) alone is not enough to prevent 4E-BP1 from sequestering eIF4E. EIF4E must be free to bind to eIF4G in order for protein synthesis (i.e. recovery from training and net muscle growth) to begin. Insulin as well as amino acids must be present at the same time as indicated by the results from the group that were fed a mixed nutrient meal. So although feeding of the carbohydrate meal resulted in elevated blood glucose and elevated insulin levels, carbohydrates alone are not sufficient to allow protein synthesis to begin.
2. The only group that experienced a significant drop in cortisol levels was the mixed meal group. The carbohydrate-only group showed that neither blood glucose nor insulin had any effect on reducing cortisol levels. In contrast, the mixed meal group showed cortisol levels even below those in the control group who did no exercise and were also fed the same meal.
It would have been nice for the authors of this experiment to explore the effect of the fat content in the "mixed meal". From the results we saw that cortisol was lower in the mixed meal group. We can only speculate whether this was due to the protein, the fat, or some combination of protein, fat and carbs. Further research in this area should take into consideration all components of the post exercise meal. One other issue that might be addressed in humans is the time frame during which re-alimentation is critical to "long term" adaptation to exercise.
In closing...
Pre- and post-exercise nutrition is critical if one wants to maximize the anabolic effects of exercise. The pre-exercise meal should be high in a quickly digestible protein. This will ensure high delivery of amino acids to the muscle tissue. Carbohydrates can also be taken in to minimize glycogen loss and suppress catabolic hormones. Fat should be avoided pre-exercise unless the exercise is for endurance.
The post exercise meal should consist of carbohydrate, protein and perhaps a small amount of essential fats, in a form that is easily and quickly digestible. There are many meal replacement products that fit the bill. Just pick the one you like the most. Don't worry about sugar content because right after a workout, fat storage is not a big issue. A liquid meal is the most practical method of post-exercise feeding although it is probably not essential. The ratio of macronutrients depends somewhat on the nature of the training session. An emphasis on high glycemic carbs, complete readily digestible proteins such as whey, egg, or high quality casein, and essential fats such as fish or flax oil will meet the criteria for an effective post exercise meal."
Pozdrawiam, Dezir - doradca w dziale 'fitness'
-----------------------------------------------
Low carbs diet user
http://pumpingiron.w.interia.pl
oto art:
BEFORE
Pre-workout nutritional strategies are based on providing alternative energy substrates (mainly carbohydrate) to preserve energy stores, and taking advantage of increased blood flow to muscle tissue.
Carbohydrates
High intensity exercise places great demand on glycogen stores. Glycogen is the sugar stored in the liver and muscles. Because high intensity exercise burns energy at such a high rate, the body is unable to supply sufficient oxygen to be able to use fat for fuel. Instead, it must use sugar both stored in the muscle and brought in from the blood.
Consuming simple sugars right before training can reduce the amount of glycogen used during exercise. This can prolong performance. More importantly, higher blood sugar and insulin levels appear to create a hormonal milieu favorable to anabolism (growth).
During exercise, cortisol accelerates lipolysis, ketogenesis, and proteolysis (protein breakdown). This happens in order to provide additional fuel substrates for continued exercise. The effects of cortisol may also be necessary to provide an amino acid pool from which the muscle can rebuild new contractile proteins if there are insufficient amino acids delivered from the blood. This ensures that some degree of adaptation can occur regardless of the availability of dietary protein. Over time however, if this process is not balanced with additional dietary protein, the net effect will be only maintenance or even a decrease in functional muscle tissue, as is evident during periods of starvation or prolonged dieting. Fortunately, there is only a non-significant rise in cortisol levels when carbohydrates were consumed during exercise. (Tarpenning, 1998) The net effect is a more rapid increase in the cross sectional area of the muscle fibers with the greatest effect seen in type-II fibers.
This may be a less expensive option for those who were thinking of using phosphatidylserine. In this case, carbohydrate administration appears to down regulate the hypothalamic-pituitary-adrenal axis, probably through insulin or perhaps through the presence of carbohydrate itself. This would, in effect, greatly reduce the body's catabolic response to exercise stress. All good news for bodybuilders.
"Protein
Another pre-workout strategy involves taking advantage of increased blood flow to working muscles. Because the availability of amino acids is often the limiting factor for protein synthesis, a pre-workout protein meal will enhance the delivery of amino acids to muscle tissue. Research has demonstrated the effectiveness of a pre-workout protein drink.
Delivery of amino acids has been shown to be significantly greater during the exercise bout when consumed pre-workout than after exercise (Tipton, 2001). There is also a significant difference in amino acid delivery in the 1st hour after exercise, with the pre-exercise protein drink providing a significant advantage. Net amino acid uptake across the muscle is twice as high with a pre-workout protein drink as compared to consuming it after. Phenylalanine disappearance rate, an indicator of muscle protein synthesis from blood amino acids, was significantly higher when amino acids were taken pre-workout. These results indicate that the response of net muscle protein synthesis to consumption of a protein solution immediately before resistance exercise is greater than that when the solution is consumed after exercise, primarily because of an increase in muscle protein synthesis as a result of increased delivery of amino acids to the leg.
post
Protein
Protein is another critical nutrient post-exercise. Protein is essential to post exercise anabolism. Protein provides amino acids that are used to rebuild damaged tissues as well as provide enzymes and carrier proteins necessary for adaptation to exercise. Without protein, which supplies essential amino acids for endogenous protein synthesis, the body's ability to adapt to exercise is greatly diminished.
Studies have shown a 12 to 14 day period after the onset of an unaccustomed exercise program, in which nitrogen balance, the ratio of protein intake to protein loss, is negative (Butterfield 1987). Any study looking at protein needs and exercise must take this into account. Nitrogen balance during this period appears to be insensitive to total caloric intake, but can be improved with a high protein intake if adequate calories are supplied (Gontzea 1975). Even though additional protein intake will prevent nitrogen balance from becoming negative, it will still fall despite high protein intake during the first two weeks of exercise.
Muscle specific messenger RNA (mRNA) produced subsequent to training has a half-life of only 4-5 hours. It is so short because mRNA has no "quality control" mechanism built into the coding. By keeping the half-life short, any errors in the sequence won't be able to produce enough defective proteins to do irreparable damage to the cell or organism. This also allows tight control of protein metabolism.
The timing of protein intake is important. If the anabolic stimulus from exercise is to be maximized, a steady flow of amino acids must bathe the muscle while mRNA content is high. It should be no surprise that the optimum time for protein intake after your workout is relatively brief compared to frequency of training a particular muscle. Muscle protein synthetic rate (MPS) is elevated in humans by up to 50% at about 4 hours following a bout of heavy resistance training, and by 109% at 24 hours following training. A study done by Macdougall (MacDougall et al 1995) further examined the time course for elevated muscle protein synthesis by examining its rate at 36 hrs following a bout of heavy resistance training. Six healthy young men performed 12 sets of 6- to 12-RM elbow flexion exercises with one arm while the opposite arm served as a control. MPS was calculated from the in vivo rate of incorporation of L-[1,2-13C2] leucine into biceps brachii of both arms over 11 hours. At an average time of 36 hours post-exercise, MPS in the exercised arm had returned to within 14% of the control arm value, the difference being nonsignificant. The following conclusions can be drawn from this study, following a bout of heavy resistance training, muscle protein synthetic rate increases rapidly, is more than double at 24 hours, and then declines rapidly so that at 36 hours it has almost returned to baseline.
Current recommendations for total protein intake for athletes is between 1.6-1.8 grams per kilogram body weight, depending on who you read, however, it is not uncommon for bodybuilders to consume in excess of 2 grams per kg of body weight with no ill effects. It should be remembered that the body does not have the capacity to effectively store amino acids. Protein should be eaten at least every 3-4 hours. The evening meal should contain slowly digesting protein that will allow a steady release of amino acids into your system well into the night. Dinner is a perfect time for steak or other meat dishes."
"It's about synergy
As mentioned earlier, macronutrient intake modulates post-exercise protein synthesis in ways that are just beginning to be understood. Yes, protein is required to supply essential amino acids for protein synthesis, but what is the mechanism by which protein is controlling this process? Also, are carbohydrates and fats needed only for fuel replacement, or do they play an "interactive" role in post exercise protein synthesis? Recent research has shed light on these questions.
Researchers from the Division of Nutritional Sciences at the University of Illinois examined the effect of post exercise meal composition on protein synthesis. To do this, they looked specifically at the activity of specific proteins known to regulate protein synthesis at the translational level.
Initiation of translation (the binding of mRNA to the ribosomal pre-initiation complex) requires group 4 eukaryotic initiation factors (eIFs). These initiation factors interact with the mRNA in such a way that makes translation (the construction of new proteins from the mRNA strand) possible. Two eIFs, called eIF4A and eIF4B, act in concert to unwind the mRNA strand. Another one called eIF4E binds to what is called the "cap region" and is important for controlling which mRNA strands are translated and also for stabilization of the mRNA strand. Finally, eIF4G is a large polypeptide that acts as a scaffold or framework around which all of these initiation factors and the mRNA and ribosome can be kept in place and proper orientation for translation.
The researchers in this study looked at the association of the mRNA cap binding protein eukaryotic initiation factor-4-E (eIF4E) with the translational inhibitor 4E-eukaryotic initiation factor binding protein-1 (4E-BP1) in the acute modulation of skeletal muscle protein synthesis during recovery from exercise. Fasting male rats were run on a treadmill for 2 h at 26 m/min and were fed immediately after exercise with saline, a carbohydrate-only meal, or a nutritionally complete meal using Ensure Powder (54.5% carbohydrate, 14% protein, and 31.5% fat). Exercised animals and non-exercised controls were studied 1 h post-exercise.
Muscle protein synthesis decreased 26% after exercise and was associated with a fourfold increase in the amount of eIF4E present in the inactive eIF4E.4E-BP1 complex and a concomitant 71% decrease in the association of eIF4E with eIF4G. Refeeding the complete meal, but not the carbohydrate meal, increased muscle protein synthesis equal to controls, despite similar plasma concentrations of insulin. Additionally, eIF4E.4E-BP1 association was inversely related and eIF4E.eIF4G association was positively correlated to muscle protein synthesis. This study demonstrates that recovery of muscle protein synthesis after exercise is related to the availability of eIF4E for 48S ribosomal complex formation, and post-exercise meal composition influences recovery via modulation of translation initiation.
The results of this study tell us a few things:
1. Insulin (via carbohydrate intake) alone is not enough to prevent 4E-BP1 from sequestering eIF4E. EIF4E must be free to bind to eIF4G in order for protein synthesis (i.e. recovery from training and net muscle growth) to begin. Insulin as well as amino acids must be present at the same time as indicated by the results from the group that were fed a mixed nutrient meal. So although feeding of the carbohydrate meal resulted in elevated blood glucose and elevated insulin levels, carbohydrates alone are not sufficient to allow protein synthesis to begin.
2. The only group that experienced a significant drop in cortisol levels was the mixed meal group. The carbohydrate-only group showed that neither blood glucose nor insulin had any effect on reducing cortisol levels. In contrast, the mixed meal group showed cortisol levels even below those in the control group who did no exercise and were also fed the same meal.
It would have been nice for the authors of this experiment to explore the effect of the fat content in the "mixed meal". From the results we saw that cortisol was lower in the mixed meal group. We can only speculate whether this was due to the protein, the fat, or some combination of protein, fat and carbs. Further research in this area should take into consideration all components of the post exercise meal. One other issue that might be addressed in humans is the time frame during which re-alimentation is critical to "long term" adaptation to exercise.
In closing...
Pre- and post-exercise nutrition is critical if one wants to maximize the anabolic effects of exercise. The pre-exercise meal should be high in a quickly digestible protein. This will ensure high delivery of amino acids to the muscle tissue. Carbohydrates can also be taken in to minimize glycogen loss and suppress catabolic hormones. Fat should be avoided pre-exercise unless the exercise is for endurance.
The post exercise meal should consist of carbohydrate, protein and perhaps a small amount of essential fats, in a form that is easily and quickly digestible. There are many meal replacement products that fit the bill. Just pick the one you like the most. Don't worry about sugar content because right after a workout, fat storage is not a big issue. A liquid meal is the most practical method of post-exercise feeding although it is probably not essential. The ratio of macronutrients depends somewhat on the nature of the training session. An emphasis on high glycemic carbs, complete readily digestible proteins such as whey, egg, or high quality casein, and essential fats such as fish or flax oil will meet the criteria for an effective post exercise meal."
Pozdrawiam, Dezir - doradca w dziale 'fitness'
-----------------------------------------------
Low carbs diet user
http://pumpingiron.w.interia.pl
Pozdrawiam, Dezir - (były, więc nieoficjalny) moderator działu "Fitness"
----------------------------------------------
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