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The Truth About Protein Absorption: How Often You Should Eat Protein to Build Muscle

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The Truth About Protein Absorption: How Often You Should Eat Protein to Build Muscle

Many people claim that the body can only absorb so much protein per meal, and that you must eat protein every few hours to build muscle. Are they right?

 

Many different numbers are perpetuated in this myth. Some “experts” claim you shouldn’t eat more than 40 grams of protein per meal, whereas others give lower numbers, and yet others higher.

Who’s right?

Well, as with many issues of nutrition, there’s no simple answer.

It would stand to reason that an NFL linebacker’s body deals with protein intake differently than a 120-lb weakling’s. Protein needs due to lifestyle and lean mass should influence the matter of protein metabolism, right?

Additionally, if it were true that a person can only absorb a relatively small amount of protein in one meal, then “super-dosing” daily protein needs into 2–3 meals would result in protein deficiencies. This assumption begs the question of how the human species survived the hunter-gatherer days, but the body IS incredibly adaptive.

So, how much protein can we eat and absorb in one sitting, and how often do we have to eat protein to build muscle?

The Science of Protein Absorption

In order to better evaluate the issue at hand, let’s look at what actually happens when you eat protein.

First, your stomach uses its acid and enzymes to break the protein down into its building blocks, amino acids. These amino acids are transported into the bloodstream by special cells that line the intestines and are then delivered to various parts of the body. Your body only has so many transporter cells, which limits the amount of amino acids that can be infused into your blood every hour.

This is what we’re talking about with “protein absorption”—how quickly our bodies can absorb the amino acids into our bloodstreams.

It’s widely known that the human body absorbs different proteins at different rates. According to one review, whey clocks in at 8–10 grams absorbed per hour, casein at 6.1, soy at 3.9, and egg at 1.3. These numbers aren’t completely accurate due to the complexities involved in measuring protein absorption, but they lend insight nonetheless: certain proteins are absorbed very slowly, whereas others can be quite fast.

You should also know that food substances don’t move uniformly through the digestive tract, and they don’t leave sections in the same order that they arrived in.

For instance, the presence of protein in the stomach stimulates the production of a hormone that delays “gastric emptying” (the emptying of the food from the stomach), and that slows down intestinal contractions. This causes food to move more slowly through the small intestines, where nutrients are absorbed, and this is how your body buys the time it needs to absorb the protein you eat. Carbohydrates and fats can move through and be fully absorbed while your body is still working on the protein.

The next step in protein metabolism occurs once the amino acids make it into the blood stream. Your body does various things with them, such as tissue growth and repair, and it can temporarily store (up to about 24 hours or so) excess amino acids in muscle for future needs. If there are still amino acids in the blood after doing all of the above, your body can break them down into fuel for your brain and other cells.

If that’s how your body processes proteins we eat, what’s up with the claims that it can only absorb so much in one meal?

The Problem With Fixed-Number Claims Regarding Protein Absorption

Claims that the body can only absorb so much protein in one sitting are usually based one or two things:

1. An ignorance of how food moves through the digestive system. Some people believe that all foods move through the small intestines in 2–3 hours. Thus, they believe, even if you ate even the fastest type of protein that can be absorbed at a rate of 8–10 grams per hour, you could only absorb 25–30 grams of protein in one meal. If you ate  protein that is absorbed more slowly, then you would (apparently) wind up with even fewer grams absorbed into the bloodstream.

Well, as we now know, your body is smarter than that, and regulates the speed at which protein moves through the small intestines to ensure it can absorb all of the available amino acids.

2. References to studies relating to the anabolic response to protein consumption. A study commonly cited in connection with protein absorption showed that 20 grams of post-workout protein stimulated maximum muscle protein synthesis in young men. That is, eating more than 20 grams of protein after working out did nothing more in terms of stimulating muscle growth.

The most obvious flaw in this argument is you can’t use studies on the anabolic response to protein consumption to extrapolate ideas about how much we can absorb in one sitting. Acute anabolic responses to eating protein don’t give us the whole picture. Absorption relates to the availability of amino acids over extended periods of time, which prevents muscle breakdown and provides raw materials for growth. And, as we now know, our body doesn’t just throw away all of the amino acids it can’t immediately use—it can store them for later

Further supporting this position is a study conducted by the Human Nutrition Research Center. It had 16 young women eat 79% of the day’s protein (about 54 grams) in one meal or four meals over the course of 14 days. Researchers found no difference between the groups in terms of protein synthesis or degradation. 

Furthermore, if we look at the amount of protein used in the above study relative to body weight, it comes out to about 1.17g/kg. Apply that to a man weighing 80 kilograms (176 pounds), and you get about 94 grams of protein in one sitting. While this isn’t definitive scientific proof, it’s food for thought.

Research on the style of dieting known as intermittent fasting is also relevant. This style of dieting has people fasting for extended periods, followed by anywhere from 2–8-hour “feeding windows.” One study found that eating the entire days’ worth of protein in a 4-hour window (followed by 20 hours of fasting) didn’t negatively impact muscle preservation.

Before we move on, I want to quickly address something mentioned earlier, which is the study that showed that 20 grams of post-workout protein stimulated maximum protein synthesis in young men. Don’t assume that this 20-gram number applies to everyone.

Protein metabolism is affected by several things:

  • How much muscle you have. The more you have, the more amino acids your body needs to maintain your musculature, and the more places your body can store surpluses.
  • How active you are. The more you move around, the more protein your body needs.
  • How old you are. The older you get, the more protein your body needs to maintain its muscle.
  • Your hormones. Elevated levels of growth hormone and insulin-like growth factor 1 (IGF-1) stimulate muscle synthesis. If your body has high levels of these anabolic hormones, it will utilize protein better than someone that has low levels.

On the other hand, elevated levels of cortisol reduces protein synthesis and accelerates the process whereby the body breaks down amino acids into glucose (gluconeogenesis), thereby reducing the amount available for tissue generation and repair. Some people have chronically elevated cortisol levels, and this impairs protein metabolism.

So, while 20 grams of protein might be enough to stimulate maximal muscle growth in certain conditions, this won’t hold true for everyone. Some people will need more to reach the same level of synthesis, and others will be able to benefit from more protein (it will result in more protein synthesis).

The Bottom Line:
You Can Be Very Flexible With Your Protein Intake

As you can see, it’s impossible to put a cap on how much protein your body can absorb in one meal. It’s definitely a hell of a lot more than the 20–30 grams that some people claim.

You probably also noticed that protein timing isn’t as important as some people think, either. You don’t have to eat protein every 2-3 hours to maximize muscle growth or avoid going catabolic. Total intake over 24-hour periods is what really matters, not regular feedings.

While it’s smart to have a good amount of protein before and after training, break up the rest of your daily needs however you want and let your body take care of the rest.

Personally, I like to eat every few hours, but if you prefer fewer, larger meals, then don’t be afraid to load up on the protein when you eat.

 

What are your thoughts on protein absorption and timing? Have anything else to add? Let me know in the comments below!

 

If you liked this article, then you’ll love this book…

Eating enough protein is only one part of building a strong, muscular, lean physique. It takes BOTH proper nutrition and proper training to transform your body. 

The truth is if you know how to train, eat, and rest properly, then you can build muscle and lose fat every week…and actually see the changes in the mirror.

And that’s why I wrote Bigger Leaner Stronger for men, and Thinner Leaner Stronger for women: they lay out EVERYTHING you need to know about diet and training to build muscle and lose fat effectively…

The Book Bigger Leaner Stronger by Michael Matthews.

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admin I’m Mike Matthews and I’ve been training for nearly a decade now. I believe that every person can achieve the body of his or her dreams, and I work hard to give everyone that chance by providing workable, proven advice grounded in science, not a desire to sell phony magazines, workout products, or supplements. More about me.

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72 Comments
  • Shay

    This is a very well written and extremely informative article. I have always had the question whether I was having excess protein at one sitting. The concept mentioned above should definitely go to the future editions of BLS. Thank you!

    • Michael Matthews

      Thanks Shay! I’m really glad you liked it.

      This is actually in Muscle Myths, along with a bunch of other interesting odds and ends. :)

  • Devon

    Hi Michael,
    I just stumbled onto your site and really like the way you present your information. I just got your LBS and in it you identify maximum levels of protein absorption in one sitting. Is this information that you learned and started to apply recently, or did I misread something in LBS? I understand that the industry changes quickly, and new info is coming out all the time, so when I noticed a few contradictions between the LBS book and a few of the articles I’ve had the pleasure to read on your site, I thought I’d get your take. Thanks for all the hard work!

    • Michael Matthews

      Thanks Devon!

      Yeah in BLS I give a general recommendation of not going over 80 grams of protein in one sitting simply to be on the safe side. There IS a point where your body will be wasting aminos, and the reality is eating more than that is quite uncomfortable anyway.

      Let me know if you run into anything else and I’ll clarify.

    • davort

      Thanks Devon for asking this question. I had the same dilemma since I’ve also read Mike’s advice on max amount of protein in a meal, with respect to protein absorption.

      I’m a big fan of Intermittent Fasting mostly because I find it more intuitive than eating 5-7 small meals a day (a meal every 2-3 hours).

      That being said, and having in mind that I’m a 240-lb guy, my meals often contain around 80-100 grams of protein (I usually have lunch, a PWM whey shake and dinner). So, imagine my disbelief after reading that line in BLS! :)

      • Michael Matthews

        Haha yeah that should be fine. I wanted to give a simple, safe number in BLS as there is enough for someone to think with as it is.

        • davort

          Yeah, I figured that was the case ;) Thank you Mike, you’re doing a really awesome job with both inspiring and educating us! Kudos!

          • Michael Matthews

            Thanks man! I really appreciate it. :)

  • Danno

    Nice article Mike. I think you also stated in one of your books, that you should try to get some protein in every meal, which is a great tip as well.

    • Michael Matthews

      Thanks! Yeah it’s good general advice for hitting high protein numbers every day. Eating 60-80 grams at a time can be a chore.

  • Matt

    Great stuff! Keep it coming Mike!

    • Michael Matthews

      Thanks Matt!

  • Kasey Milligan Sanchez

    Great article my awesome crazy Floridian friend. Keep em’ coming. Very informative!

    • Michael Matthews

      Thanks yo! :P

  • Mark E.

    In you article where you mention how protein synthesis is affected by several things, how do you know which factors are having the most impact? This question was specifically raised in my mind when I saw the hormone factor. (Quote)

    “Elevated levels of growth hormone and insulin-like growth factor 1 (IGF-1) stimulate muscle synthesis. If your body has high levels of these anabolic hormones, it will utilize protein better than someone that has low levels.

    It would be good to know how to understand my body in these areas so as to adequately eat the proper portions. Can you elaborate more on these areas by chance?

    • Michael Matthews

      Good question.

      The reality is you don’t have to worry about this as variations in levels of anabolic hormones like testosterone, IGF-1, etc. don’t make a difference until you get above and beyond physiological normal (i.e., take steroids).

      The bottom line is if you’re lifting regularly, you want to get around 1 gram of protein per pound of body weight.

      • Mark E.

        Oh, I understand now. Keep up the great work!

        • Michael Matthews

          Great, thanks!

  • Mark E.

    our hormones. Elevated levels of growth hormone and insulin-like growth factor 1 (IGF-1) stimulate muscle synthesis. If your body has high levels of these anabolic hormones, it will utilize protein better than someone that has low levels.

    The question was raised in my head. How do I know my IGF-1 levels and insulin to better understand my protein intake? As well as the other factors you had mentioned as playing a part in protein synthesis. This one stood out the most. How do I better understand my body in these areas?

    • Michael Matthews

      Sorry for the late reply. I missed this somehow.

      You can get your hormones tested but changes within the physiological normal won’t make a difference in the end.

      To really affect protein synthesis in a way that you would see in the gym and mirror, you need to exceed the normal physiological ranges, and that’s only accomplished with steroids.

  • Eric

    As always, great article!! Congrats!!!

    One thing that’s not very clear to me yet is that I’ve always heard out that if we eat too much protein, what the body doesn’t absorb in aminos (after that 24-hour period ‘in stock’) turns into fat storage. I didn’t find that in your article (correct me if I’m wrong). So is that fake someway? The protein will never turns into fat storage in the process?

    Thanks :>

    • Michael Matthews

      Thanks Eric!

      The energy cost of turning ingested protein into body fat is VERY high. It’s a non-issue.

  • Pingback: The Truth About Protein Absorption: How Often You Should Eat … | Biochemistry Blog: Biochemistry Online Help

  • Harriet

    Thanks for a nice article.

    “whey clocks in at 8–10 grams absorbed per hour, casein at 6.1, soy at 3.9, and egg at 1.3″ ?

    Is the missing unit here an hour? Meaning 8-10 g casein absorbs in 6.1 hours, or 6.1 grams of casein absorbs per one hour?

    Can you give a list/table of different proteins and absorbing times? I am interested also in hemp, bean and rice (I cannot use anything made of milk).

    • Michael Matthews

      The body can absorb about 8-10 grams of whey protein per hour, 6.1 grams of soy protein per hour, and 1.3 grams of egg protein per hour.

      Regarding the vegan sources of protein, check out this article to learn more:

      http://www.muscleforlife.com /the-best-protein-powder-for-women/

  • David Tripp

    What about complete versus incomplete proteins (those that contain all the essential amino acids versus those that don’t)? What percentage of complete proteins in your daily total protein intake is optimal for building muscle? And would timing be important there too?

    • Michael Matthews

      This is a myth. All forms of protein are “complete.” Some just have higher or lower amounts of specific amino acids.

      You can read more about this here:

      http://www.muscleforlife.com /the-best-protein-powder-for-women/

      • David Tripp

        Thanks, Mike, very interesting. So let me ask a slightly different question… We all know the best whole foods for supplying your daily protein are lean beef, chicken, turkey, fish, dairy and eggs, right? But when you’re counting your protein intake in grams for each day, are you including the smaller amounts of protein found in other whole foods including fruits and veggies (and legumes and grains)? Or are you counting only the protein from the best sources such as the whole foods listed above and quality protein supplements?

        • Michael Matthews

          Yes, those are great sources of protein.

          Yup, I do count protein in other sources, but honestly 95% of my protein is coming from animal sources so the plant proteins are just incidental, really.

      • nucleon

        While I agree with a lot of what you say, i’d like to point out that all forms of protein are most definitely not “complete”. There are 20 different amino acids that make up all proteins, in different combinations. 9 of the 20 are referred to as “essential”. This means that the body cannot synthesise them and so they have consumed from one’s diet. The other 11 are non-essential, because our bodies can make them. Some proteins contain some amount of all 9 essential amino acids. This applies to almost all proteins from animal sources. Other proteins, often from plant sources, do NOT contain all 9 essential amino acids, and are thus referred to as “incomplete”. If your diet contains only incomplete protein sources, you MAY end up with deficiencies of certain amino acids. The result is that your body may be unable to make those proteins that contain the amino acid or acids that you’re not eating enough of.

        There’s a way around this , however. If you eat 2 different incomplete protein sources, whereby one lacks amino acid A while the other lacks amino acid B, then a combination of the 2 proteins will still yield all amino acids. A combination of 2 such proteins is called “complementary”. It’s the reason why vegetarians don’t necessarily have protein deficiencies. It’s standard advice given to parents of children in poorer countries where meat is expensive, so that kids can still get all essential amino acids, from cheaper, plant sources. A typical example is a cereal-legume combination eg rice and beans.

        • Michael Matthews

          Thanks for the comment!

          The “complete” and “incomplete” protein myth was debunked by MIT years ago but it still persists. I recommend you read their study:

          http://ajcn.nutrition.org/content/59/5/1203S.abstract

          It’s been 100% disproven that certain plant proteins are “incomplete” and must be combined to form “complete” proteins.

          What IS true is that certain types of proteins have better amino acid profiles than others–are higher in essential amino acids–than others, but none are completely without.

  • Mike

    Cheers Mike! Good stuff, you’re dynamite!
    -Mike from Finland

    • Michael Matthews

      Thanks MIke! :)

  • Fahim Khan.

    Michael, thank you for clearing about Protein intake per meal. I was confused over this for past few months. Now I understand it much better. :)

    • Michael Matthews

      YW! I’m glad I could help!

  • Pingback: What is the Best Protein Powder for Building Muscle? | Muscle For Life

  • Derrek

    What’s your take on intermittent fasting to lose weight? Thanks!

    • Derrek

      Sorry, I just found your article on it. Thanks!

      • Michael Matthews

        No worries!

  • Douglas Proud

    Mike, I’ve asked before but it looks like here that you’re telling me that I can only get bigger by taking steroids??? As I said in my earlier posts,,,,,,,,,,I lift 3-4 x a week but I can;t seem to gain more size. I’m doing the protein and vits but is this it!!???

    • Michael Matthews

      Lol what? I never recommend that someone take steroids.

      If you’re not gaining weight/muscle, it’s simply because you’re training and/or eating incorrectly…

  • Douglas Proud

    Quick response…………I’ve gone to less reps, heavier weights and less time in between. Upped my protein intake and working until I can’t lift. Think that’ll do it???

    • Michael Matthews

      Work in the 4-6 rep range, take 2-3 minutes of rest in between sets, and make sure you eat enough and you will make gains.

      You should also check out my book Bigger Leaner Stronger. It goes over everything you need to know really…

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  • António Alves

    Hey Mike,

    here you said like you do many times that it is hard to train with intensity. What about having a low carb diet but eating some carbohydrates before and after your workout?

    And if yes, how much would you think is ok?
    Right now I have a low carb diet due to some health issues, but the doctor does allow me to eat some carbs during the day.
    Do you think that 1 or 2 small bananas plus the usual protein shake after the workout and some whole wheat crackers before the workout is a good option?

    • Michael Matthews

      Hey!

      Good question. Low-carb diets result in chronically low glycogen levels, so unfortunately just having some carbs before and after training won’t cut it.

      If you’re going low-carb for health reasons, stick with it and I would recommend having about 30 grams before training, and pretty much all the rest after training.

  • http://www.facebook.com/timthepierce Tim Pierce

    so… to some up, just eat all the protein you want as you want and roughly your body will do the rest.

    Thanks F for that

    • Michael Matthews

      Basically. :)

  • Pingback: How Much Protein is Needed to Build Muscle | Muscle For Life

  • noorbindra

    can i have protein intake about 50 grams along with other micro nutrients found in like oats, peanut butter, nuts, almonds blended all together with milk powder?

    • Michael Matthews

      Yup, sounds delicious.

  • Alan

    Mike, can you clarify one thing for me. If after a workout I take only protein (whey powder) without any carbs or fat, how can I be sure that the body will use the protein as the source for building/repairing the muscles, and not as an energy source? After the workout the body is starving to get energy…

    • Michael Matthews

      Good question. I wouldn’t necessarily say the body is starving for energy after a workout, and amino acids are used preferentially for tissue repair before they are used to create glucose.

      The bottom line is having just protein after working out is totally fine.

  • chris1234

    Mike,
    Have you done any articles with in depth look at cortisol? I know sleep and not overtraining help keep cortisol from interfering. Any color you could add or direct to a link with more??
    Thanks for what you do.

    • Michael Matthews

      No I haven’t, but I’m going to do one on cortisol and weight loss soon.

      Yes, getting enough sleep and not overtraining are the two major ways to keep your cortisol in a healthy range. There are some natural substances that can help as well, which I will be including in my multivitamin.

  • Diunte

    If I want to increase my muscle size, do I lift heavy 6-10 reps or 4 to 8 reps?

  • Nachelov

    Mike, in your “15 Recipes” book on your newsletter, you talk about how we should eat protein every 3-5 hours. Guess the book was written before the researches found in this article? ;)

    • Michael Matthews

      Haha yep! Thanks for bringing that up–I will fix it!

  • Syed Own

    Short concise and well presented, and perfect article; thank you mate.

    • Michael Matthews

      Thanks Syed!

      • tigerfire

        So I’m pretty new to weight training and protein and just wanted to know if I’m on the right track. After my morning workout I eat a serving of Kashi go lean (13g protein) with a serving of whey protein powder (30g) in one serving of soy milk (8g). I’m 6’1 215lb male. is this a good start to my day?

  • Pingback: MFL Podcast #5: Best protein powder, signs of overtraining, laws for happy living, and more… | Muscle For Life

  • Sergio

    great article, very goo presentation of the idea Michael !

    • Michael Matthews

      Thanks!

  • Sergio

    and thank you !

    • Michael Matthews

      YW!

  • PlainTalkToronto

    Great article but left me with one question …… does this in anyway undermine the BV value of different proteins? I am assuming that the BV values still remain true of various protein sources.

    • Michael Matthews

      Thanks! BV isn’t really an issue unless you rely primarily on plant-based proteins.

  • simon turay

    You’re the man Mike! I really like how you present your material. Everything is referenced and in a logical order.

    I also like the way you acknowledged Nachelov’s comment – it shows great pragmatism and character.

    Keep up the good work

    • Michael Matthews

      Thanks! I really appreciate it. :)

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