Dec 18 2015, 05:34 PM, updated 11y ago
Yes. This is one of the most frequent question asked around.
Forewarning: No broscience and qi gong activists please.
I saw this on reddit. (LINK: https://www.reddit.com/r/Fitness/comments/3...ts_talk_about/)
QUOTE
Cararacs: I was asked by a few people to post this here, so here you go:
I do realize here that the passion is fitness, but as a science advocate I think it's just as important to know how your body works. If you have a basic understanding oh human physiology you can easily sift through all the bullshit pseudoscience and incorrect information thereby making highly informed decisions for yourself and be confident.
The whole point of this post is this paper which reviews over 150 original research papers about dietary protein, absorption, protein recommendations, how it changes with age, meal protein composition, etc. It is, however, a scientific review paper, written in a scientific journal, so it may be a more difficult read to some. But I do recommend that if you have the time to sit down and read it. Please, don't be discouraged if you have to do a quick google on science jargon or physiology concepts. So, what is the difference between a review paper in a scientific journal vs. a review of science literature on a blog? In a literature review the manuscript has to be read by a few scientists that are considered experts in the field. If they don't agree with the information presented in the paper, or if vital information is left out then the paper isn't published; this isn't a perfect system, but it's better than nothing. However, because of this, review papers talk about contradictory findings and why they might exist.
Hopefully some of you will find this information helpful.
I do realize here that the passion is fitness, but as a science advocate I think it's just as important to know how your body works. If you have a basic understanding oh human physiology you can easily sift through all the bullshit pseudoscience and incorrect information thereby making highly informed decisions for yourself and be confident.
The whole point of this post is this paper which reviews over 150 original research papers about dietary protein, absorption, protein recommendations, how it changes with age, meal protein composition, etc. It is, however, a scientific review paper, written in a scientific journal, so it may be a more difficult read to some. But I do recommend that if you have the time to sit down and read it. Please, don't be discouraged if you have to do a quick google on science jargon or physiology concepts. So, what is the difference between a review paper in a scientific journal vs. a review of science literature on a blog? In a literature review the manuscript has to be read by a few scientists that are considered experts in the field. If they don't agree with the information presented in the paper, or if vital information is left out then the paper isn't published; this isn't a perfect system, but it's better than nothing. However, because of this, review papers talk about contradictory findings and why they might exist.
Hopefully some of you will find this information helpful.
QUOTE
Summary of the paper:
Absolutely, also I am not sure if I can send pdfs through reddit, but if that is possible then I will be more than happy to do that too. They do start off by saying that excessive protein intake is hard on the kidneys, so over time eating WAY more than what is needed isn't the best idea. It should also be noted that endurance and athletes and bodybuilders will have more protein requirements and the ability to absorb more. Yet, as a reminder most people, even those who enjoy lifting regularly are NOT bodybuilders and endurance athletes.
A positive relationship was established between the dietary protein intake and the change in lean body mass (LBM) and a daily protein intake of 1.0 g/kg body weight (BW) was established as sufficient Whereas, in sedentary young and elderly men and women, a daily protein intake of 0.85 g/kg BW was found to be adequate, indicating that persons participating in resistance training may need a higher protein intake than sedentary persons, which has become "common" knowledge in the fitness world. Although if you take some time off (few days), it is recommended to stay at 1g/kg BW. A study showed that no muscle was lost or no loss in protein intake after 7 days of bed rest. However, even increased protein intake did NOT prevent muscle loss or decline in whole body protein absorption during 14 days of bed rest. At this point it didn't matter if you ate .8g/kg BW or 1g/kg BW. This just gives evidence that the body does adapt during periods of activity vs inactivity.
MPS = muscle protein syntesis
MPS rate levels off with increasing dose of protein, this levels off at around 20g. Supporting evidence shows that diets containing 1.5 or 3.0g protein/kg LBM/day in both young and elderly had NO difference in MPS. This is evidence that higher protein diets do NOT enhance MPS. And by higher it's meant beyond the dietary needs of your body. The main way of looking at protein absorption is analyzing plasma amino acid (AA) concentration. When consuming a protein rich meal, the protein will eventually be digested and absorbed as AA. When muscles need repairing, this will start a complex cellular cascade to repair the torn and damaged muscle tissue that results from resistance training. When the plasma is enriched with AA it will stimulate myofibril MPS (important component of muscle fiber), but this only lasts for UP TO 1 hr.
Even if there is a high concentration of plasma AA for 4-6 hrs. This means that saturating you system with protein or AA will not continuously stimulate this myofibril MPS aka new muscle fibers. Now, some proteins are better at this than others, this is why whey protein is so popular. But 25g of whey is all that is need to increase myofibrillar MPS synthesis to roughly 180 min. Note that 25g is the threshold and consuming 30+ grams of whey is irrelevant having no benefits. In fact, some research has shown that high doses of protein can have the OPPOSITE effect. This is a phenomenon and is hypothesized in the paper as a result of inhibitory signaling involving the endoplasmic reticulum (ER) stress. The ER is a place in the cell where AA are put together making proteins. When this protein synthesis system is flooded, it shuts down preventing new protein to be made. There is a lot of research looking at the best way to prolong new muscle synthesis (myofibril MPS). One paper is cited stating that continues feeding of AA to the muscle for 8 hours is the best way. Since previous data shows that over flooding is bad, I can only deduce that eating smaller quantities of protein over the day is best. This phenomenon is termed the full muscle or muscle full concept. Evidence also suggests that diets higher in essential AA (EAA) or amino acids that our bodies cannot make are better at triggering the synthesis of new muscle fiber. For example Leucine in an important EAA for muscle and is found in meat and plants.
Eating a meal high in EAA after weight training is the best (ergo why whey is so popular), but another study showed that the plateau was reached at 20g of protein. The study fed people 10g, 20g, 30, and 90g of beef protein in young men and women and looked at plasma AA and muscle biopsies to see MPS. When it comes to whole whey vs (chocolate) milk argument. Whey initiates MPS faster, but casein (component in milk) has less of an effect but MPS lasts longer (but not as robust). Fat content was found to effect casein absorbance and effectiveness: less fat the better. This is about 2/3 of the paper and all that I have time for now. This paper does go into the effects of aging quite a bit; mainly looking people 50+ yrs. Really all you need to know is that elderly need less protein (can't absorb it) and high protein diets are even worse because their kidneys are older and higher protein diets are strenuous.
Absolutely, also I am not sure if I can send pdfs through reddit, but if that is possible then I will be more than happy to do that too. They do start off by saying that excessive protein intake is hard on the kidneys, so over time eating WAY more than what is needed isn't the best idea. It should also be noted that endurance and athletes and bodybuilders will have more protein requirements and the ability to absorb more. Yet, as a reminder most people, even those who enjoy lifting regularly are NOT bodybuilders and endurance athletes.
A positive relationship was established between the dietary protein intake and the change in lean body mass (LBM) and a daily protein intake of 1.0 g/kg body weight (BW) was established as sufficient Whereas, in sedentary young and elderly men and women, a daily protein intake of 0.85 g/kg BW was found to be adequate, indicating that persons participating in resistance training may need a higher protein intake than sedentary persons, which has become "common" knowledge in the fitness world. Although if you take some time off (few days), it is recommended to stay at 1g/kg BW. A study showed that no muscle was lost or no loss in protein intake after 7 days of bed rest. However, even increased protein intake did NOT prevent muscle loss or decline in whole body protein absorption during 14 days of bed rest. At this point it didn't matter if you ate .8g/kg BW or 1g/kg BW. This just gives evidence that the body does adapt during periods of activity vs inactivity.
MPS = muscle protein syntesis
MPS rate levels off with increasing dose of protein, this levels off at around 20g. Supporting evidence shows that diets containing 1.5 or 3.0g protein/kg LBM/day in both young and elderly had NO difference in MPS. This is evidence that higher protein diets do NOT enhance MPS. And by higher it's meant beyond the dietary needs of your body. The main way of looking at protein absorption is analyzing plasma amino acid (AA) concentration. When consuming a protein rich meal, the protein will eventually be digested and absorbed as AA. When muscles need repairing, this will start a complex cellular cascade to repair the torn and damaged muscle tissue that results from resistance training. When the plasma is enriched with AA it will stimulate myofibril MPS (important component of muscle fiber), but this only lasts for UP TO 1 hr.
Even if there is a high concentration of plasma AA for 4-6 hrs. This means that saturating you system with protein or AA will not continuously stimulate this myofibril MPS aka new muscle fibers. Now, some proteins are better at this than others, this is why whey protein is so popular. But 25g of whey is all that is need to increase myofibrillar MPS synthesis to roughly 180 min. Note that 25g is the threshold and consuming 30+ grams of whey is irrelevant having no benefits. In fact, some research has shown that high doses of protein can have the OPPOSITE effect. This is a phenomenon and is hypothesized in the paper as a result of inhibitory signaling involving the endoplasmic reticulum (ER) stress. The ER is a place in the cell where AA are put together making proteins. When this protein synthesis system is flooded, it shuts down preventing new protein to be made. There is a lot of research looking at the best way to prolong new muscle synthesis (myofibril MPS). One paper is cited stating that continues feeding of AA to the muscle for 8 hours is the best way. Since previous data shows that over flooding is bad, I can only deduce that eating smaller quantities of protein over the day is best. This phenomenon is termed the full muscle or muscle full concept. Evidence also suggests that diets higher in essential AA (EAA) or amino acids that our bodies cannot make are better at triggering the synthesis of new muscle fiber. For example Leucine in an important EAA for muscle and is found in meat and plants.
Eating a meal high in EAA after weight training is the best (ergo why whey is so popular), but another study showed that the plateau was reached at 20g of protein. The study fed people 10g, 20g, 30, and 90g of beef protein in young men and women and looked at plasma AA and muscle biopsies to see MPS. When it comes to whole whey vs (chocolate) milk argument. Whey initiates MPS faster, but casein (component in milk) has less of an effect but MPS lasts longer (but not as robust). Fat content was found to effect casein absorbance and effectiveness: less fat the better. This is about 2/3 of the paper and all that I have time for now. This paper does go into the effects of aging quite a bit; mainly looking people 50+ yrs. Really all you need to know is that elderly need less protein (can't absorb it) and high protein diets are even worse because their kidneys are older and higher protein diets are strenuous.
SOS: https://www.reddit.com/r/Fitness/comments/3...ets_talk_about/
TL;DR
- MPS rate levels off with increasing dose of protein, this levels off at around 20g. Supporting evidence shows that diets containing 1.5 or 3.0g protein/kg LBM/day in both young and elderly had NO difference in MPS
- deduce that eating smaller quantities of protein over the day is best.
- Evidence also suggests that diets higher in essential AA (EAA) or amino acids that our bodies cannot make are better at triggering the synthesis of new muscle fiber.
- Eating more protein doesn't mean more muscle growth
- a daily protein intake of 1.0 g/kg body weight (BW) was established as sufficient
I, myself, an advocate of 0.8g per lb of BW, surprised from reading this. Got me thinking if I'm over consuming.
I would like to hear inputs from you guys on this.
Dr. [darklight97], your input is very much appreciated
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