Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
9 Jul

Dear Mark: How Much Protein Can You Absorb and Use from One Meal?

steakEarly last week, I received an email from a reader. The subject was protein absorption, and it referred to something I’d written several weeks past in this post on Leptin Reset among other things. I had suggested that your body can only deal with about thirty grams of protein in one sitting. I immediately realized that this statement wasn’t nuanced enough and might give the wrong impression, so I explained what I meant in a bit more detail in the comment board. After receiving the following email (thanks for keeping me honest, Brandon!) I figured I would revisit this topic and further articulate what we know about the human body and dietary protein utilization.

Let’s go.

Hi Mark,

I had a question about protein intake. In an older post, you mentioned something about anything beyond 30 grams of protein in a single meal likely being turned into glucose or fat, but I’ve heard different things from others. So, how much protein can you really use in one meal?

Brandon

First off, “meal” is the key word, one that I omitted in my original statement. Eating 50 grams of straight protein – and protein alone, whether it’s whey protein or 99% fat-free lean sirloin – is probably going to have a different effect than eating a mixed meal which contains 50-some odd grams of protein in addition to fat and digestible, fermentable, and insoluble carbohydrates. In other words, protein is rarely eaten alone. It’s eaten atop salads, alongside veggies, with starches, and it often comes imbued with animal fat (as meat). It’s eaten as a meal.

Digestion takes a long time, and it’s not a segmented procession of different meals through the gastrointestinal tract. Food isn’t separated into “meals” in your stomach. It’s just all food, all mashed together. If you still have breakfast in your stomach when your lunch enters the picture, lunch and breakfast will meet and mingle. Stomach acid breaks the food down into a big semifluid mass of partially digested food components, water, digestive enzymes, and hydrochloric acid – all referred to as chyme.  When the chyme is “ready,” it’s pushed through the duodenum (where nutrient extraction begins) and into the intestines.

Once the protein part of the chyme has been broken down by enzymes into amino acids, amino acid absorption by the intestines can begin. Amino acid transporters  grab amino acids and transport them through the cells lining the intestinal wall and from there into the bloodstream to be delivered to other parts of the body. But because the pool of amino acid transporters is limited, amino acids are typically absorbed by the small intestine at a rate of 5-10 grams per hour. This would suggest, at first glance, that the original “30 grams of protein per sitting” figure is close to correct. If you can only absorb, say, 7 grams of protein per hour, and the bolus of digested protein and other foods takes 4 to 5 hours to wind its way through the intestine, you’re gonna absorb maybe 28-35 grams. Right?

Not exactly. It turns out that our digestive process is fairly fine-tuned and regulated by the composition of whatever’s being digested. The presence of protein in chyme actually causes the secretion of CCK, a hormone that slows down the intestinal contractions that move food along, thus giving the protein more time to be transported by amino acid transporters. So, while it’s technically true that we aren’t absorbing 30 grams (let alone more) of protein all at once, it will eventually be absorbed.

Clearly, a fair amount is directed to normal tissue growth and repair. If it’s much more than that, a few possibilities enter the picture. Some will be directed towards a short term storage option referred to as the “labile protein reserve.” In this case, skeletal muscle tissue will take up some of the excess amino acids and simply store then for possible near future use (like within a day or so or for emergencies). Beyond that, your body will want to oxidize excess amino acids directly for fuel or convert them to glucose in the liver via gluconeogenesis. It will convert the nitrogen from the amino acids into ammonia and you will excrete that in your urine. If levels get too high in the bloodstream, your pH will shift (more acidic) and calcium will be called upon to balance pH out again. As we have seen with some people going full Primal, larger intakes of protein can offset lowered carb intake by generating significant rises in glucose through gluconeogenesis. Indeed, there are a lot of options the body has when you eat a high protein meal.

I still wouldn’t “stuff” myself on protein. If you have to force feed that lean chicken breast, perhaps your body’s trying to tell you something. Upon digestion, excess carbs and fat can be limitlessly and easily absorbed and assimilated (as body fat or glycogen) or burned off, but excess protein still requires extra work. Protein digestion produces toxic metabolites that we can usually get rid of, even on higher protein intakes, but there’s clearly a limit. Our bodies finding protein to be extremely filling? Our intestines actually slowing down the digestive process when protein is present? This is just how our bodies absorb protein at their own pace. They take their sweet time, but they get it all.

Okay, so we do absorb most of the protein we eat, whether it’s a 30-gram whey shake that’s absorbed in a couple hours or a large porterhouse whose protein is absorbed in ten hours. We’re not pooping amino acids. But are we using all that protein? Is it doing uniquely proteiny stuff, like building muscle? Or will everything above 30 grams get converted into glucose?

That depends. Many factors affect how your body utilizes a given amount of protein:

Body Size

If you’re a bigger person (longer limbs, more potential spots for amino acids to be utilized), you can handle more absolute protein, and that protein will be more likely to go toward muscle protein synthesis.

If you’re smaller, the reverse is true. You simply don’t need as much absolute protein for structural demands, and you’ll have a lower threshold before protein becomes an energy substrate. If you eat the same steak as the bigger guy (all else being equal), you won’t “use” as many of the amino acids as he will.

Activity Level

Are you sedentary? You require less protein. Your muscles aren’t getting the signal to build and grow stronger and adapt to an imposed demand. The RDA of 0.36g/lb bodyweight should suffice.

Are you moderately active, jogging here and there, maybe riding the bike to work once or twice a week, and doing some basic lifting in the gym? You can use a bit more, as physical activity increases protein demand.

Are you actively trying to pack on muscle mass, and working out accordingly? You can use a lot more protein, up to and perhaps even over 1g/lb bodyweight.

Age

Muscle maintenance in the elderly seems to require larger relative amounts of dietary protein. In one study, the RDA of 0.36g/lb bodyweight wasn’t enough to prevent some muscle catabolism.

Stress Level

Chronic stress, as indicated by chronically elevated cortisol levels, reduces muscle protein synthesis (protein doing proteiny stuff) and increases gluconeogenesis (conversion of protein into glucose).

It’s also worth noting that amino acids do other stuff, too, beyond building muscle and providing energy substrates when in excess. It’s not as if amino acids that don’t go toward rippling pecs are immediately converted into glucose. No, they’re also:

  • Taken up by the intestines, both as an energy source for the small intestine and to form a reserve pool of amino acids that the body can draw upon during fasting or starvation (when there’s little to no dietary amino acids input) instead of breaking down skeletal muscle to turn into energy, at least in rats.
  • Precursors for various neurotransmitters (like serotonin and dopamine).

So, to answer the question – yes, we’re probably absorbing all the protein we eat, but, depending on what we’re doing with our time, how old we are, how large or small we are, how active we are, how much we’re lifting, and how much stress we’re under, we’re all using the protein we absorb in different ways and proportions. As is often the case, the answer brings up even more questions. But that’s okay, because that’s just something else to explore.

Until next time, Grok on!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Thanks for this article… It has been something I’ve been wondering recently.

    zack wrote on July 9th, 2012
  2. “So, to answer the question – yes, we’re probably absorbing all the protein we eat, but, depending on what we’re doing with our time, how old we are, how large or small we are, how active we are, how much we’re lifting, and how much stress we’re under, we’re all using the protein we absorb in different ways and proportions.”

    This is all I needed to read. :) And, it’s what I assumed. Protein has many functions and depending on what we are doing, it’s going to be used in different ways in different bodies.

    Hmm… that word “depend” again. It’s all about context.

    Primal Toad wrote on July 9th, 2012
    • +1

      doghug wrote on July 9th, 2012
    • So….Eat ALL the protein!

      Graham wrote on July 9th, 2012
      • pretty much! because in the end, it will be absorbed and used in different ways depending on your level of activity and other factors as mark mentioned

        Josh Singer wrote on July 10th, 2012
    • What if we lift 3x a week, and are fairly sedentary outside of the gym and on rest days? Do we just lower our intake on the rest days but are okay the other days? This concerns me because today was my rest day and I forced 206 grams of protein today. Eek!!

      Jess wrote on January 20th, 2013
      • Hi Jess

        Did you get a response here ? i also want to know if to lessen protein intake on non training days and increase on training days.

        thanks a mill

        tanya wrote on February 25th, 2014
        • I’m not Jess or Mark, so I’m not sure how interested you are in my opinion, but one thing to remember is that you’re still growing when you’re resting.

          Jackson Blakeman wrote on February 26th, 2014
  3. Thanks for this. I tried the 50g of protein at breakfast for a few days. I had to force it down, which didn’t feel right. Also I noticed I got really hungry at 11am. I seem to do much better on about 20g of protein for breakfast. About 3 eggs is perfect. That keeps me going to lunchtime. I think the extra in the 50g must have converted to glucose and raised my insulin, so then I had a sugar crash.

    Nick wrote on July 9th, 2012
    • My experience exactly Nick, I got a little excited when at first on the primal diet but after a little self experimentation, a cheesy 3 egg omelette with salad for breakfast does the trick nicely. Especially when complemented with macademia nuts c.11!

      Patrice wrote on July 10th, 2012
    • That’s really interesting that you crahs after the big meal of protein. that usually would keep me full forever.. lol

      Yea usually I do two bacon strips, two eggs for breakfast and some veggies. then down some coconut milk with honey to keep me full longer.

      Gift Clumsywarrior wrote on July 10th, 2012
    • I’m a type 1 diabetic and find that eating protein NEVER raises my blood glucose. Obviously if i eat carbs it does straight away but i can easily eat just a meal of protein (100+ grams) with no diffrenece to blood sugar and i dont have to inject insulin to counter act it. If it doees raise it it wouldnt be till much later as the process for conversion to glucose it a lot more long winded than the carb process. Now i’m not sure if my gluconeogenesis works differently but i think as a non diabetic if you do manage to raise your blood sugar through protein the rise would so miniscule that it would barely register and the affects of that would barely be felt. If anything i’d say it’s because your cortisol pushed up your blood sugar and it dopped later but it wouldnt crash. I’d say dont eat ‘breakfast’ and try Intermitent Fasting and you’ll feel better. Best resource for IF is here, w w w.leangains.com

      greg white wrote on July 10th, 2012
      • I too am a type 1 diabetic, but I can see when glucogenesis is happening. I lift heavy things 4 times a week, and thus am on a fairly high protein diet, but if I am eating more than 40 or maybe 50 grams of protein in a meal, I’ll see my blood sugar go up a bit. Not a lot, but enough.

        Obviously with steaks the protein is going to be broken down/absorbed/used a lot slower than with a whey protein drink, but it is still noticeable. Granted, I also check my blood sugar at least 6 times a day, so…

        Leangains rocks for me too, btw.

        –Me

        Adam wrote on July 10th, 2012
        • That’s interesting. I’m now thinking am i paying enough attention to my readings after eating protein. I’m like you in that i test about 6 tmes day, strategically, before meals, 2 hours after, then another hour after that, as dictated by how my insulin works.
          Could you tell me what do you find your readings go up to and by how much when affected by the protein?
          Yep Martin Berkhan is a legend, i pretty much listen to Martin and Mark, then make my own mistakes.

          greg white wrote on July 11th, 2012
  4. I IF pretty much every day, and eat about 70g of protein upon waking. I feel like I can devour protein, it’s not a problem for me.

    mi'khael wrote on July 9th, 2012
    • I’ll do 40g in whey at 5:AM and be ready for more protien at 9:AM.

      The wifey has been doing it too with cottage cheese (whole fat) as the second dose.

      Her leptin balance is starting to kick in and her craving for food at dinner is diminishing.

      More fun than doing nutrition research on yourself is doing nutrition research on a loved one.

      Kenny wrote on July 9th, 2012
    • I don’t think you can really call it IF when you do it “pretty much every day.” Doesn’t sound very intermittent to me.

      Clark wrote on July 31st, 2012
  5. I have been stalling lately and heard in a podcast from Rob Wolf that he recommends having 1 gram of protein per pound of body weight or more for leaning out. I’ve been wondering if I am in starvation mode and not getting enough protein. Typically I fast all day and have a 1/2 rib eye from Costco or a Pork chop or two with a ton of veg, later I might make a couple eggs or have an apple with a small amount of nut butter. I never feel like I am starving myself. I’m pretty close to my goal and think I have been overthinking all of this a bit. Anyone have any advice about protein amounts for leaning out?

    Steve wrote on July 9th, 2012
    • it doesnt seem like you are getting enough protein if that is all you are eating. half ribeye or a pork chop will be about 40g and a couple eggs another 14g. I would also vary your eating pattern. I eat between 2-3 times per day, never more, and occasionally just once. but variety keeps your body from going into starvation mode. since starting, I dropped from 15% to 5% body fat, increased energy, and have had no trouble maintaining it for a few months now.

      eric wrote on July 9th, 2012
    • Its 1g per pound of LEAN body weight.

      Clippies wrote on July 10th, 2012
      • ok, the recommendation is .7 or 1.0 or whatever gram amount protein per pound of LEAN BODY WEIGHT. My Newbie question is…How do I compute present lean body weight. Do I need a DEXA scan or is it simple arithmetic.. present overweight minus BMI ideal = current lean mass? Will that work? If you lose the overweight and achieve the ideal BMI weight, it will still be composed of lean muscle weight and some amount of fat…. Should daily protein intake be based on current weight or on the weight you are hoping to achieve….that could be a big difference, right?

        lisa scorr wrote on November 29th, 2014
  6. Great article, Mark. I don’t come here all the time, but I’ve been working with a trainer for the past year to build muscle, and he’s always of the mindset that I need to eat 5-6 small meals a day because of the whole “only 30 g. of protein get absorbed at once” theory. I just can’t do it – I feel sick forcing food in my face so often. I’ve found anywhere from 2-4 equal meals a day works great for me. I’m a female, 5’4″ age 34, weighing 124 lbs. at 21% body fat, so I’m in pretty good shape, and I can easily eat 50-60 g. protein at a meal – for example yesterday I ate a half a pound of chicken with an entire bunch of kale for lunch and I felt great, didn’t feel sick, wasn’t forcing it, etc. My body needed it because I’ve been training hard. it’s good to know 50g. at once or 50 g. spread out over the course of the day probably isn’t going to make a difference in my muscle gains/fat loss goals.

    Jaime wrote on July 9th, 2012
    • Your trainer is using ‘science’ that is totally wrong. You dont need to eat the 5 – 6 meals a day, it old, it’s outdated, it just plain BS and it’s been scientifcally proven as incorrect. Go to here and look around, this man would tell you to dump your PT NOW! Serioulsy get rid of the PT, if he cant be bothered to keep up to date and spout BS at you then spend your hard earned elsewhere. go here and read up w w w leangains.com. Mark links to this website and regularly uses the site as a reference point.

      greg white wrote on July 10th, 2012
      • w w w.leangains.c o m/2010/10/top-ten-fasting-myths-debunked.h t m l

        here’s the link again with spaced included to avoid moderators

        greg white wrote on July 10th, 2012
      • So glad I read this! I’m so sick of people telling me to force-feed myself 6 times a day.

        Jess wrote on January 20th, 2013
        • 5-6 meals a day is fine. I believe it is optimal to promote a healthy metabolism. The goal here is to never be hungry and never be full. None of these meals require stuffing food into your body, 3 of these meals may could a handful of nuts between b-feast and lunch. Or a yogurt, piece of fruit, or granola bar between lunch and dinner. The B-Feast should be relatively small (OJ, Toast with peanut butter, and a fruit or yogurt), lunch a little more substantial, and a modest dinner size(one pork chop instead of 2, whole rice or sweet and a salad).

          The idea is you feed your body in small amounts every 2-3 hrs so the nutrition is used most effectively and your metabolism remains in high gear. At 150lbs, I lost 10lbs just from altering the timing of meals with the same amount of calories.

          Eric, your weight loss is most likely due to reduced calories. If you resume a regular full 2000 cal diet you will likely gain a few pounds given your eating schedule. If you split that same 2000 cals into 5 meals you could probably still maintain your weight and have a more balanced nutritional profile.

          geoff wrote on February 9th, 2014
    • greg white wrote on July 10th, 2012
  7. I’ve tracked my intake a few times and practically effortlessly take in about 1 gram per lb of body weight. I’m also working out and trying to gain muscle so I think my body is taking full advantage of what I’m eating. Interesting to read this though.

    katie wrote on July 9th, 2012
    • Katie, how long have you been trying to gain muscle? Im interested to see if the 1 gram of protein per pound of body weight works for gaining muscle?

      Max Ungar wrote on July 9th, 2012
  8. So, in this case, a smaller person should be eating less protein? What if they are trying to gain muscle mass? or what if a larger person is trying to lose muscle mass? should they eat less protein, because it could be converted into glucose?

    This is also the first time I have heard that excess protein can be converted to glucose. If this is true, then does that mean that when we eat protein, and dont exercise, or eat any carbs we are still eating excess glucose?

    Max Ungar wrote on July 9th, 2012
    • show me someone trying to loss muscle mass and ill show you a liar

      Jake wrote on July 9th, 2012
      • see: body builders

        Max Ungar wrote on July 9th, 2012
        • I know a few. Jake speaks the truth. Anyone thinking different is buying into some MSM myths.

          Kenny wrote on July 9th, 2012
    • Excess anything can be converted to just about anything. Our bodies are kinda awesome like that, but I think the point at which you overdose on protein and begin to do damage probably coincides with getting “the meat sweats” for the fifth meal in a row.

      Graham wrote on July 9th, 2012
      • “meat sweats” :-)

        dawn wrote on July 9th, 2012
    • [quote]If this is true, then does that mean that when we eat protein, and dont exercise, or eat any carbs we are still eating excess glucose?[/quote]

      As Mark himself might say, “It depends.”

      Gluconeogenesis happens “on demand,” so the conversion happens only if the body needs more glucose than it has at any time, for example, building glycoproteins (body structures) creating mucin (to lubricate the intestines, your eyes, your lungs, etc.). If there’s no need for extra glucose, and your amino acid reserves are full, excess goes out with other body wastes.

      Our bodies evolved to be flexible and sophisticated in handling nutrients from foods. There’s rarely a situation where only one thing can happen in response to any typical kind of eating. Even getting fat is a the end stage of a series of adaptive responses to excess carbs.

      jake3_14 wrote on July 16th, 2012
  9. I eat one meal per day and I ain’t wastin’ away :)

    Groktimus Primal wrote on July 9th, 2012
  10. Thanks Mark. I have been trying to figure out what’s going on with my liver. Doc says my “enzymes are too high,” although I do not have fatty liver. I have been IFing to give it a rest. Now I know how it handles protein. Cool!

    Harry Mossman wrote on July 9th, 2012
    • ohh, which enzymes?? My bilirubin was high for a very long time, so for about a year, i did a high fat (lots of coconut products), low carb/very low carb diet and I also took some supportive liver supplements/herbal remedies. The following year I had my blood work done and everything was back to normal. I suggest looking into liver health supplements by Solaray, but also do your research! Dandelion and Milk Thistle are two great herbs to check out

      Hilary wrote on July 9th, 2012
  11. Does it really matter when you consume protein after you work out? (Heavy lifting)

    Marisol wrote on July 9th, 2012
    • Consuming protein after a workout will minimize DOMS delayed onset muscle soreness, and aid in recovery. Protein after a workout is much more important than carbs. I aim for about 20g whey, and max 5-10 carbs.

      eric wrote on July 9th, 2012
    • Rather than whole protein, I took Martin Berkhan’s advice and took some Branched Chain Amino Acids (BCAA)pre- and post-workout. I can now work out hard and more frequently without DOMS. BCAA is the only supplement I’ve ever used that has such an obvious effect.

      jake3_14 wrote on July 16th, 2012
  12. very interesting post. as a small female, i’ve often wondered about protein absorption. i also found your thoughts on chronic stress & protein true, as i think we are at such a disadvantage (overall) when we are stressed.

    Marissa wrote on July 9th, 2012
  13. Proteiny…the next new word. Predecessor: Bootylicious

    Caleigh wrote on July 9th, 2012
    • Haha. Yes!

      Cherice wrote on July 9th, 2012
  14. I am celebrating three months primal today! Bacon for everyone!! LOL :D

    primal aly wrote on July 9th, 2012
    • Caleigh, not sure why your pretty pic is showing on my post… :)

      primal aly wrote on July 9th, 2012
  15. “We’re not pooping amino acids” – brings up a related question I’ve not seen addressed:

    Does our body *always* use *all* the useful carbs, fats, and protein we take in?

    Or is part of the puzzle of weight loss and energy balance that our bodies poop excess (unneeded) carbs, fats, or protein? Is that why some people stay skinny, not because their metabolisms increase, but because their bodies are simply better at discarding excess?

    Put another way, in all the gazillions of weight loss studies out there, has anyone measured the ‘residual’ energy content in the ‘poop’ of the participants?

    I’ve never seen anyone address this. Has anyone else?

    John wrote on July 9th, 2012
    • Very good question! With all the recent talk about the intestinal biome, I have wondered also about the ingested food that is used by the biome to fuel its own growth and energy requirements. A little known factoid (that may have been mentioned here before): somewhere around 60 percent of your fecal matter by weight is dead bacteria. Has to be using some of the food…

      BillP wrote on July 9th, 2012
      • you crap mostly bacteria and fiber.

        mark wrote on July 10th, 2012
      • I know that for me, corn on the cob leaves my body un-utilized.

        jake3_14 wrote on July 16th, 2012
    • The Japanese are “recycling” protein via burgers. hehe

      Paleo Bon Rurgundy wrote on July 10th, 2012
      • I’ve heard they’re feeding it to prisoners to keep costs low.

        Animanarchy wrote on July 10th, 2012
  16. Thanks Mark. Questions: Why would you need anything other than protein from a macronutrient stand point? My thinking is that if excess protein creates glucose then aren’t we getting sugar (carbs) indirectly through protein? Going one step further, if the excess glucose is causing an insulin response and pushing excess glucose into our fat stores aren’t we also ultimately getting, in effect, useable fat in the form of bodyfat? Obvious a protein only diet is not effective unless your goal is to die so what is wrong with my thinking? It seems to be understood that people can starve eating exclusively very lean foods like fish or lean game, therefore I would love to know what I am missing in my logic. Also, is the known insulin response to protein simply a response to gluconeogenesis or are there different mechanisms inherent to protein digestion itself that cause insulin spikes?

    David Cole wrote on July 9th, 2012
    • Your cell membranes and many key tissues are composed primarily of fats/lipids. If the only fat in your body is converted glucose going into adipose tissue, I don’t see how your body could maintain itself, especially since in converting from protein to other nutrients you lose a lot of energy.

      Steve P wrote on July 9th, 2012
    • Protein only diets are entirely possible, but this is dependent partly on genetics. The Inuit don’t eat vegetables because nothing grows in the Arctic Circle for much of the year, and yet they have thrived (right up until the point when they started eating western food like sugar and flour and it all went to hell).
      Similarly, it has been shown in some remote communities that diets consisting mainly to entirely of fatty fish like salmon provide all the required nutrients for those populations.

      That doesn’t mean every Tom Dick or Harry can go to an all protein diet and live well – we have evolved based on many factors, including the food sources available to our ancestors over the last quadrillion years.
      There’s also the issue of whether the protein source you’re consuming itself contains the necessary nutrients – I definitely wouldn’t try living exclusively off non-organic chicken, even with the skin on, for example.

      Clare wrote on July 9th, 2012
      • My understanding is that the diets of the far northern meat-eaters (Inuit included) have the majority of their calories from animal fats – seal and caribou are very high in fat.
        Farley Mowatt, in the book ‘The People of the Deer’, describes how inland Inuit actually didn’t bother with harvesting the abundant, large fish in their lakes because they knew they had to eat animal foods with enough fat in them to survive. They also tried to hunt the caribou heavily in the fall (when stored fat reserves were highest) to maximize the fattiness of the animals they hunted.
        ‘Rabbit starvation’, a sickness that occurred when trappers tried to live exclusively off of lean rabbit meat, was known and feared in the North.
        It seems that an all-meat diet is entirely possible, but not an all-protein diet.

        markkuto wrote on July 9th, 2012
      • Clare – Nothing to add except that your avatar is made of WIN.

        Jaradel wrote on July 10th, 2012
      • Ya markkuto you are right they always cherished the fat the most, when the caribou were lean they would worry because they knew “sickness would follow”. They always ate the fattiest parts of the animal first and the lean meat was actually given to the dogs. We can’t live entirely off protein, since we have “essential” fatty acids not to mention all the other great nutrients fat contains. We also need protein for our “essential” amino acids still looking for those essential carbohydrates though…

        Cassidy wrote on July 11th, 2012
    • The liver cannot metabolize more than about 200-300g of protein (convert to glucose) per day. That will give your at most 1200 Cal. The remainder of your calories must come from fat or carbohydrates. A pure protein diet leads to a condition called “rabbit starvation” where people who eat plentiful protein with no fat (rabbits) starve despite the intake of ample calories.

      Paul wrote on July 9th, 2012
  17. Gluconeogenesis can be a nasty little trick if you are diabetic. I (and many diabetic friends) have found that protein over a certain amount causes spikes in blood sugar. Some proteins like whey isolate, can spike pretty quickly because it is often eaten in a protein bar or shake without much fat. If it is coming from a steak, then the spike may take 4-5 hours.

    After testing a bit later than my normal 1 and 2 hour marks, I found that anything over 30g caused undesirable blood sugar spikes. I think I lasted 2 days on the whole 50g/morning leptin reset before admitting that keeping stable blood sugar was more important than testing fun internet theories. :)

    So if you have a blood sugar meter, test and find your own personal protein limit.

    Daytona wrote on July 9th, 2012
    • I’m type 1 and dont personally dont find this a problem. Out of interest, as a non-diabetic reading does your blood sugar spike to?

      greg white wrote on July 10th, 2012
      • Are you on an insulin pump, or do you use self-dosed insulin?

        Joshua Naterman wrote on December 21st, 2012
    • GNG is not the primary culprit there. Glucagon is most likely what caused your experiences… allow me to explain.

      The liver has a maximum rate of 27.7 g of glucose per hour coming from GNG according to clinical data. That’s at full tilt, in starvation mode, when the body has to do whatever it can to stay alive.

      It takes 1.6g of whole protein to make 1g of glucose. Regression shows us that this means it takes 44.3g of protein to make 27.7g of glucose.

      Maximal intestinal absorption of whey protein, and super lean proteins like pork tenderloin, is 10.7 g/hour.

      That means that, at most, the body can make 10.7/1.6 = 6.7 g of glucose in 1 hour from dietary protein. Furthermore, resting GNG levels are typically between 7 and 10g/hour of carbs because this is the anaerobic demand of the average body at rest.

      The 15-15-15 rule is that 15g of glucose (pure) ingested should raise blood sugar by 15 points in 15 minutes. That’s how we get hypoglycemic rehab patients to safe blood sugar levels when it’s time to do cardiac rehab, and is also why glucose is kept there as well as why blood glucose tests are used at every rehab session with a diabetic.

      So, we need to look somewhere else. If you start reading through the research archived on PubMed, what you will find is that when you ingest protein alone your body releases glucose from the liver, often in a large and rapid spike.

      This is to cause the pancreas to secrete insulin, which facilitates transport of the protein and glucose into the cells.

      The hormone that causes the glucose release from the liver is called glucagon.

      Since you do not respond well to physiological levels of insulin (which is what makes you diabetic), the sugar simply piled up in your blood.

      You are absolutely right to have made the adjustments that you made, but I feel that it is important to understand what was really going on behind the scenes so that you understand your body and your condition a bit better.

      It’s also good for people to understand exactly how this works in healthy people: Exactly the same.

      The difference is that we, the non-diabetic population, are capable of absorbing all that sugar and protein because we respond properly to endogenous insulin production!

      However, now you’ve lost glucose from the liver. If you aren’t eating carbs, and there is a deficiency in the liver, you have only one place to get more carbs… GNG from protein.

      You end up wasting a fairly large portion of that protein spike on GNG instead, perpetuating a cycle that does interfere with ideal lean mass increases and also has the potential to generate dangerous amounts of nitrogenous waste. This is generally not a problem if:

      A) you have no background of genetic kidney dysfunction or impairment, either directly in your body or through family history

      B) you are staying within the known safe limit of 2.8 grams of protein per kg of body mass, which is 1.27g protein per pound of body weight.

      C) You are at least consuming enough carbohydrate to take care of your resting anaerobic metabolism. This is not very much.

      If you are eating the right carbs at the right time, which is the subject of a large article or a small book if we want to properly explain it, and are taking in frequent moderate doses of protein, like 30g at each meal, you will keep yourself healthy AND capable of high performance… all without falling into the traps of “I need more protein! MOOOOREZZZZ!!!” and “If all I eat is protein, I’ll be healthier!”

      To keep it short, the right carbs come from fresh fruits and vegetables. Not pasteurized juice, and not even fresh juice (unless you’re blending all the pulp back in, and even then you’re changing the absorption curve dramatically). Whole foods. It’s fine to cook them, and most should be cooked (preferably steamed if you’re into getting as many nutrients as possible, as this only degrades ~10% of total nutrient content while actually breaking open so many cells that the net effect is GREATER absorption).

      Joshua Naterman wrote on December 21st, 2012
      • As a T1D who’s been trying a ketogenic diet – THANK YOU. I’ve been experiencing spikes after most meals. Generally, I take whatever protein I’ve consumed and then bolused for 60% of that number over the course of three hours. My control has been incredible, but I’m not losing any weight, and I think it’s because of the insulin that I’m giving myself over and above my basal.

        I’m think I’m going to start limiting myself to 30g of protein and a piece of fruit per meal. And while I know you indicated that the “right carbs at the right time” is a tricky subject, if you had to give a best guess – how many grams of carbs per meal would you say is a good starting point? Currently, it’s maybe 1-2g per meal.

        Thanks again.

        Paul Martin wrote on December 28th, 2012
  18. This is an awesome article. You get so much BS propaganda from Vegans and the like its not even funny. Meat is digested and absorbed. All those fruits and veggies arent. We dont poop meat chunks.

    matthew dooley wrote on July 9th, 2012
    • Funny. I never thought about it that way, but it is true.

      getfitkatie wrote on July 12th, 2012
  19. Thanks for a great article I was wondering about this very topic. I had heard that the body could only handle so much protein at a time but it didn’t seem correct from an evolutionary sense. This cleared some thigns up.

    CMHFFEMT wrote on July 9th, 2012
  20. Your body needs protein for many things other than skeletal muscle: enzymes (both digestive and metabolic), hormones, neurotransmitters, and to form the soft tissues of your whole body (except brain, which is mostly fat). Normally, your skeletal muscles need very little pro to maintain.

    However, this changes significantly – roughly double – after a workout (I mean a real w/o, not the elliptical machine). Post w/o, your pro need goes way up, for 4 – 24 hours (depending on many factors: age, sex, intensity of w/o, etc.), until the skeletal muscles have recovered. Once they have recovered, pro need drops back to normal. E.g., 0.5 g pro/lb total bw outside post w/o window, 1.0 g pro to recover from lifting.

    http://www.jeffreybrauer.blogspot.com/2012/03/how-to-sync-diet-with-exercise.html

    Jeffrey of Troy wrote on July 9th, 2012
  21. When I started eating a Primal/Paleo diet I couldn’t get enough of meat and eggs. I could devour an entire pork loin or pot roast like it was nothing. My husband liked to show me off at restaurants and party’s because I could eat so much. Now that I’ve been eating Primal for over two years, I’ve discovered that I feel full now after one chicken breast or a small steak. I’m thinking that my body was just completely starved for protein after first going off of the SAD diet. So, maybe that’s another variable?? Someone who under ate protein significantly for a period of time might require more then the average daily recommendation for a little bit??

    Ashley wrote on July 9th, 2012
    • Same case here: fully primal for 2 years also, noticed that I cannot eat the same amount of proteins I ate two years ago.

      WildGrok wrote on July 9th, 2012
    • This is exactly what is happening to me at the moment.. I am just starting out with this Paleo way.. and I can’t eat enough meat/eggs… my prior diet was not a lot of meat, a lot of veggies and a lot of carbs. I don’t think my body knows what to do – although I am beginning to notice small changes in myself. If only I could get control of this appetite!

      Lisa wrote on July 9th, 2012
      • Don’t worry about the appetite. It will moderate itself after your body finishes making up the deficiencies. Make sure you eat enough fat, get good protein and veggies. If your experience is like mine, your appetite will moderate itself.

        Jason wrote on July 9th, 2012
    • I’m noticing this too. I’ve been Paleo for about a year and my appetite has diminished quite a bit. I go hours between meals without even trying because I’m just not hungry. I always have meat with dinner but the portions keep getting smaller. I love that my body seems to be self-regulating after years of struggling to lost weight.

      sqt wrote on July 9th, 2012
  22. This is a very specific question, but as a 210lb 24 year old male, who works in a stockroom moving 7-8 hours a day at work, plays basketball once a week and lifts 2-3 times a week, is 1 gram sufficient?

    Alexander wrote on July 9th, 2012
    • You could get away with a little more. I am 144 lbs and very active, and I prob do 150-200 g protein per day no problem. Maintain 5% bodyfat.

      Eric wrote on July 10th, 2012
      • I just saw this sorry if I’m late, but doesn’t that get expensive? Also I’m struggling to find more protein sources that don’t ramp up my caloric intake.

        Alexander wrote on July 15th, 2012
  23. Roughly 7 grams of protein per ounce of meat in general as a quick shortcut? So a half pound burger would have 56g of protein. No problem!

    Jeff wrote on July 9th, 2012
    • Eight ounces of lean ground beef would give you about 40 grams of protein. All the weight of your burger is not protein.

      Bookwyrmb wrote on July 11th, 2012
  24. I eat only protein and fat and have had the same diet for four years. I usually eat about a pound of meat at a time, only once or maybe twice a day, soaked in coconut oil. It’s easy for me to eat that much even though I am a short female. I stayed the same weight for 2+ years but now I am ten pounds over my goal. I believe it has to do with estrogen dominance, as I hadn’t been able to afford grass-fed, organic meat until very recently but I am hoping that as I transition from cheaper meat the weight will go back to my normal.

    Trisha Pena wrote on July 9th, 2012
  25. Great post, Mark. I’ve been wondering about this topic.

    For the, the most illuminating words are these:

    “As we have seen with some people going full Primal, larger intakes of protein can offset lowered carb intake by generating significant rises in glucose through gluconeogenesis.”

    I’m quite sure that explains why I didn’t lose weight in my last round of (very low carb) efforts. I suspected that was it, so it’s good to read it here.

    My revised efforts (what I’m doing now) appear to be more promising (more veggies and less protein).

    As I’ve written before: just dropping carbs to 50 or less doesn’t translate to “effortless” weight loss. There are so many other variables in the picture (as this and other posts make clear). It can take a ton of effort via trial and error to figure out what actually works for the individual.

    Susan Alexander wrote on July 9th, 2012
  26. If you eat nothing but meat and eggs for a month or so you will know generally how many eggs and how much meat to eat at your meal frequency to be full, then after that month simply add in as many carbs as you need based on exercise on a sliding 50g scale, keeps it simple. I eat lunch and dinner with a half pound of meat and 2 – 6 eggs per meal and about 5 oz of sweet potato (50g carbs a day total) and only carb load for extreme athletic events. 50g of carbs a day is plenty if your eating alot of eggs (fat) with your meat.

    Alex wrote on July 9th, 2012
  27. According to Mark we should eat about 1 gram of protein per pound of body mass each day.

    http://www.marksdailyapple.com/protein-amounts-in-food/

    I weight 200 lb. so I need to consume at least 200 grams of protein per day.

    But if my body can only absorb 7 grams per hour, the most I can absorb in a day – 24 hours – is 168 grams (24*7).

    Am I doomed to lose my lean mass?

    yuma wrote on July 9th, 2012
  28. Similar to the topic of the digestive system not separating out meals — if I’m going to eat a cookie as my cheat for today, am I better of (from an insulin spike perspective), just shoving the whole thing in my mouth and eating it or cutting it into 4 (or whatever) pieces and eating that smaller bit every couple of hours, or doesn’t it matter (basically is the single spike 4x the 4 spikes making it the same for your body or is the larger number of spikes (from a smaller amount of sugar each time) just worse no matter how big the big spike is — Thanks!

    Bee wrote on July 9th, 2012
  29. so if a large porterhouse can take 10 hours to digest, would dinner be the best time for it so you could have all night to make the most of it?

    or, on a more practical side, would it be beneficial to eat a larger amount of slower digesting protein at night? and, if so, what sources do you recommend?

    pixel wrote on July 9th, 2012
  30. I tend to eat a lot of protein nowadays because I find it helps me eat less overall.
    Still, after a few days of only eating protein my body begins to hate any and every protein, all I want then is carbs! My body is trying to tell me something. All in moderation.

    Michael wrote on July 10th, 2012
  31. Mark, you said “…your pH will shift (more acidic) and calcium will be called upon to balance pH out again…”

    This sounds like acidosis. I’m under the impression that this has been thoroughly debunked already. So far the only “evidence” I’ve seen regarding the existence of acidosis has been epidemiological in nature.

    Can you explain?

    Dan wrote on July 10th, 2012
  32. If you are looking to build muscle you must first break down your muscle fibers via lifting weights and then rebuild them by consuming foods high in protein in every meal. Building muscle requires you to constantly break down and rebuild muscle fibers. One analogy I like to use is playing with building blocks. In order to make a bigger structure you would have to first knock down the existing structure. Then you could build an even bigger structure.

    John Oxnard wrote on July 10th, 2012
  33. Didn’t think stress had to do with amounts of protein absorbed at any given time. Great info!

    Josh Singer wrote on July 10th, 2012
  34. I have read two very different versions of how to calculate our protein requirements. One is 0.36 gm/lb of LEAN or IDEAL body weight and the other that keeps popping up is 0.36 gm/lb of body weight. The difference can be huge. I am on a weight reduction diet. My goal (what I hope is my reasonable for an estimated “ideal” is 150 for my 5’7″ frame.) I am also 70 years old, but my present weight is 260. The difference is 54 grams for my lean body weight or 94 for my present body weight. That is a lot of difference. I get that as an elderly person I may need more, but as a sedentary person I may need less, so in my estimation, that comes out a draw. But should I be eating protein for my present body weight or my ideal or lean body weight? My fat cells don’t need any protein, do they?

    Bookwyrmb wrote on July 11th, 2012
    • 0.36 is, i beielive, the government advice, which is very much under what we should eat. As usual with governments advice it’s BS. It’s recommended for an active person looking to maintain or build muscle (you’ll need to maintain and probably build from the sounds of it) to aim for 1 gram protein per LEAN lb of body weight. But you should be aiming closer for 150 grams of protein, the body weight you are aiming to be, less if you aim for 15% body fat. Maybe in the range of 130 grams. So 130 grams = approx 520 calories. If you aim for 50 grams of carbs, another 200 calories, so 720 cals, and then make up the rest from good fats, at 9 calories per gram of fat. Lots of people who go primal think calories dont matter and possibly for a short while they dont as you cut out carbs but if you find the weight loss stops then you need to examing carbs and portion sizes more. Hope this helps, hopefully others can add to this as i’m a lkittle sketchy around the protein needs for the elderly.

      greg white wrote on July 11th, 2012
      • edit ”
        Lots of people who go primal think calories dont matter and possibly for a short while they dont as you cut out carbs but if you find the weight loss stops then you need to examine calroies* and portion sizes more”

        greg white wrote on July 11th, 2012
      • Thank you for your response, Greg.
        The government RDA is 0.8gm/kg of lean body weight, which, I believe, translates to 0.36gm/lb.
        Most of everything I have read in the Primal community sees this as a reasonable recommendation for the average person who is not growing, pregnant, nursing, body building, elderly or recuperating from surgery or a wasting illness. Also, I got the impression that this article was about not going overboard on protein so as to more readily control insulin spikes and therefore weight stasis or gain. Carbs and portion sizes are not the only things we have to watch!Excess protein is also a consideration. The challenge is how to compute what might be excess.
        My problem occurs when I am reading advice that leaves out what I think is an important adjective – LEAN. If we are advising people about either .36 or 1.0 gram per pound or kilogram for that matter, we cannot leave out the word lean or there will be a very big error in computation and a lot of our advisors are doing this. I just want to make sure that if Mark is saying .36gm/lb of body weight, he means just exactly that, or does he mean LEAN body weight, but just left out the adjective. If he meant body weight and not lean body weight, then I need some reasoning on why so much more protein is needed to support body fat, the tissue we are trying to get rid of.

        Bookwyrmb wrote on July 12th, 2012
  35. Intersting article. Although the article didnt really say it (or I missed it), based on the other factors, it would seem like a large dose of protein from a shake would be more likely to get converted into “other things” than would a Porterhouse due to the faster absorption of the shake. ???

    T J wrote on July 11th, 2012
  36. Great article, I have found the information very informative!

    HFIT wrote on July 11th, 2012
  37. Reading through this post transported me back to my biology class in high school.lols. But seriously, this was pretty great. I’ve never really paid attention to various factors (ie, stress levels, mobility) when I eat my way through the day.

    oceanside orthodontist wrote on July 11th, 2012
  38. Mark,

    You said…”your pH will shift (more acidic) and calcium will be called upon to balance pH out again”

    This sounds like acidosis? Hasn’t this been debunked as veg*an pseudo science?

    Dan wrote on July 13th, 2012
  39. Aha! I found what I was looking for…Apparently protein only leaches calcium from the bones if it is plant protein. Not animal protein.

    http://healthcorrelator.blogspot.com/2011/02/does-protein-leach-calcium-from-bones.html

    Dan wrote on July 13th, 2012
  40. Eating high protein does not leach calcium from the bones:

    In this intervention trial, they found that high protein diets actually improve bone health: http://jcem.endojournals.org/cgi/content/full/89/3/1169

    And in this one, they found that the increase in urinary calcium is not due to acid-base balance removing calcium from the bones, but that urinary increases in calcium are actually due to increased calcium absorption in the gut! They also noted that calcium turnover in the bones was less, but barely significant: http://jn.nutrition.org/cgi/content/full/133/3/855S

    I’m gonna go ahead and continue my super high protein diet.

    Dan wrote on July 13th, 2012

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