Different schools of nutrition argue endlessly about protein. Vegans swear it destroys our kidneys and we’re eating far too much. Strength athletes and leangains devotees can’t get enough. The government claims 56 grams/day is more than enough for anyone—yet even the most conservative and fat-friendly paleo templates recommend closer to 90 grams. Paleo eaters and omnivores enjoy pointing out that animal protein is “complete”, unlike most grain and vegetable proteins, while vegetarians and vegans swear by “protein combining”. And just about everyone gets confused when acronyms like BV, NPU, and PDCAAS enter the picture.
What Is Protein, Anyway?
Talking about “protein” is like talking about “buildings”. Just as “building” can mean a single-family home, a chemical factory, a mud-and-straw hut, a skyscraper, or the Taj Mahal, “protein” can mean anything from tiny di- and tri-peptides containing perhaps a few dozen atoms, to the giant linked chains of keratin that make up our hair and fingernails.
As such, it turns out that “protein” is a term so broad as to be nearly useless when applied to nutrition. When we’re asking the question “How much protein should we eat?” what we’re really asking is “Which amino acids do we require, what relative proportions to we require them in, and to what degree are the foods containing them digestible, bioavailable, and not otherwise poisonous or disruptive to our metabolism when ingested?”
If that sentence wasn’t immediately comprehensible to you, fear not—the purpose of this article is to explain it!
What is Protein Made Of?
Proteins are molecules made up of amino acids stuck together by peptide bonds.
Amino acids are so named because they contain both an amine group (-NH2) and a carboxyl group (-COOH). In the renderings below, we can see the carboxyl groups (the two red balls with one white ball attached) and the amine groups (the blue ball with two white balls attached). The alpha carbon, to which they’re both attached, is colored black. Here are a few examples:
Lysine
Tyrosine
Valine
Cysteine
Click here to see the 2D and 3D structure of all 21 standard amino acids.
A peptide bond occurs when the carboxyl from one amino acid bonds covalently to the amine of another—releasing a molecule of water in the process. Result: we can make just about any shape and size of protein we want by stringing together the right amino acids in a single-file chain, carboxyl to amine.
Strictly speaking, all the biologically important amino acids are alpha-amino acids, in which the amine and the carboxyl are both attached to the first carbon atom. The term “amino acid” usually refers only to the alpha-amino acids.
What Can Proteins Do?
It turns out that proteins are extremely versatile molecules. They are the basic machinery of all cells: DNA is, quite literally, just instructions for building proteins out of amino acids. They catalyze chemical reactions (“enzymes”), they signal metabolic and immune events (e.g. insulin, leptin, growth hormone, antibodies), they transport oxygen (hemoglobin and myoglobin), and they’re structural components of everything from the cytoskeleton and mitochondria of every cell to our tendons, ligaments, hair, nails, and connective tissue. Even the parts of a cell which are made from other molecules, such as phospholipids and polysaccharides, are ‘built’ by their interaction with proteins!
The average human cell is approximately 65% water, 20% protein, 12% lipid (fat), 1% RNA and DNA, and 2% “other” by mass. (Freitas 1998)
Why Do We Need To Eat Protein?
Of the 21 amino acids coded for by the DNA of multicellular organisms, adult humans can only synthesize 12 of them. The other nine must be consumed in the diet, so we call them essential amino acids.
| Essential | Nonessential |
|---|---|
| Histidine | Alanine |
| Isoleucine | Arginine* |
| Leucine | Aspartate |
| Lysine | Cysteine* |
| Methionine | Glutamate |
| Phenylalanine | Glutamine* |
| Threonine | Glycine* |
| Tryptophan | Proline* |
| Valine | Serine* |
| Tyrosine* | |
| Asparagine* | |
| Selenocysteine |
* = conditionally essential – see below
It’s actually far more complicated than “essential” or “non-essential”. Some amino acids can be converted to each other, but not created from scratch. Some amino acids can be synthesized, but not rapidly enough to meet all our metabolic needs. And children can’t synthesize some of the amino acids that adults can.
Further reading:
J. Nutr. July 1, 2000 vol. 130 no. 7 1835S-1840S
Dispensable and Indispensable Amino Acids for Humans
Peter J. Reeds
Result: humans have a non-negotiable requirement for dietary amino acids in order to sustain the basic processes of life.
Why Do We Need To Eat Protein Every Day?
Some nutrients, like vitamin B12, are stored within the body and released when needed—so though we must consume a certain amount on average, we don’t have to do so every day in order to keep ourselves healthy.
Unfortunately, we have no way to store amino acids. We have a tremendous capacity to store fat in fat cells, and a very limited capacity to store glucose (as glycogen in our muscles and liver)—but we must either use amino acids to synthesize proteins, burn them for energy, convert them to glucose, or (very rarely, and if all else fails) excrete them.
Therefore, humans have a daily requirement for each one of the amino acids necessary to life, in the quantities required by whatever proteins the trillions of cells in our bodies are making (minus our ability to synthesize some of them).
Why “Complete Protein” Is Important
Imagine a factory that assembles cars. Let’s say you have 400 wheels and tires in inventory, 200 headlights, 100 chassis, 100 engines…but only ten steering wheels. It doesn’t matter that you’ve got almost enough parts to build 100 cars: ten steering wheels means you can build ten cars. Whichever part you have the fewest of limits how many cars you can build.
Our bodies have the same problem when building proteins. For instance, lysine is an essential amino acid—so if we haven’t consumed any lysine, we can’t build any proteins that contain lysine, no matter how many of the other amino acids are available. This leaves us with two options:
- Don’t build that protein. This is not usually a viable option, as it results in signals not reaching the intended recipient, damaged cells and tissues not being repaired, pathogens not being attacked…in other words, the failure of basic metabolic processes.
- Disassemble existing tissues in order to get the amino acid(s) we need. This is known as catabolysis or ‘going catabolic’, and is what actually occurs. Muscles are the first tissues to be catabolized, as becoming slightly weaker is usually less harmful than impairing the function of other organs.
Our Summary (so far)
- Proteins form the basic machinery of all cells.
- Proteins are made out of amino acids.
- Amino acids are not interchangeable: to synthesize a protein, each one of its constituent amino acids must be available.
- Many amino acids are essential—we cannot synthesize them, and therefore must ingest them as part of our diet. Many others are conditionally essential, and cannot be synthesized or converted at the rate we require them.
- Since we have no way to store amino acids for later use, our bodies have a daily requirement for them.
- Therefore, we must ingest each amino acid, roughly in the proportion we require it, every day.
Conclusion
Our biological needs are for specific amino acids in specific proportions, but “protein” can mean any combination of one or more amino acids. Therefore, the amount of “protein” in food is, by itself, a nearly meaningless number.
I’ll discuss measures of protein quality, and much more, next week!
Live in freedom, live in beauty.
JS
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Muscles are our store of Proteins. If they were not, then we wouldn’t be able to fast at all. Also it is a myth that you lose muscles when fasting, as there is a thing called muscle memory, so that the muscles you lost build up very fast.
So in effect you don’t need to get all the amino acids daily. The only issue is that you will lose far more proteins if you consistently eat imbalanced proteins. So yes its better to consume complete proteins. This is probably why most cultures combine proteins to make them complete. Also I think Legumes are better than grains to consume isolated, because methionine in excess is a problem, while lysine is not.
90 grams a day? I honestly don’t think I could eat that low an amount of protein. I look forward to seeing where this goes.
People believe they need more protein but in fact, they eat more meat to fulfill their requirements for essential fatty acids. Protein requirements also very based on weight.
This article is full of bias and subliminal brainwashing. Lazyness with no curiosity for the absolute truth.
Excellent introduction. Autophagy of course could be a short term source for amino acids but I am not sure to what extent.
Welcome ‘back.’ (Some welcome!) Anyway, in Protein 201 will you be discussing glycogenic vs. non-glycogenic proteins? As a Type 2 diabetic I am concerned about ‘total protein’ because of the specific (glycogenic) amino acids that will convert in the liver to glucose via gluconeogenesis when eaten ‘in excess’and stored there.
For reference, my own diet (270 lb 71yo mostly sedantary male, losing 2 lb/wk)is 5% (20g)carb, 25% (75g) protein, and 70% (90g) fat, totalling 1,200kcal/day. It seems to work for me.
@Marzo – can you expand on and qualify your criticism?
@Anand Most cultures combine proteins to make them complete? There don’t appear to be any vegetarians before a couple thousand years ago, so which cultures are combining proteins?
@marzo So we won’t see you here anymore, right?
Hi J, good start. I am looking forward to the other articles in the series.
Cheers, Tony e4e
I’m still searching for protein balance in my own journey. Been on extremely low grain consumption for a year, and extremely low legume consumption for six months. Have been trying a lot of whey protein for workout recovery and found that 90-100 grams causes digestive discomfort (to put it nicely). Have dialed that back to about 30-40 grams post workout, which seems to work better. I just want to keep my muscle mass into retirement years. Other than whey, these days I get my protein from ruminants mostly with oily fish and eggs once or twice a week. Occasionally will IF or do a protein restriction day to induce autophagy.
Hope marzo doesn’t suddenly become a Paleo freak as a result of the subliminal messages in my post…
glad you’re writing some more — i’ve missed your posts! i was particularly interested in the “conditionally essential” aspect (i find i have to supplement tyrosine, myself). looking forward to hearing more!
Thank you! Looking forward to the next installment.
hurrah! nutrition updates!
read through, now to check out some of the links!
looking forward to next part.
(in addition any idea when the AHS video of you will be online?)
Likewise. Thank you, J. One article I will keep coming back to, I'm sure.
also Anand:
i think you should read what you stated again, you seem to say, simultaneously that humans do and do not lose muscle from fasting.
this is an either or situation i feel.
i think what you’re saying is
“we do lose muscle when IFing but regain it very quickly when we re-exercise and consume enough protein so it does not matter as much as we are led to believe”
i think this depends on where you are coming from. if you’re 250 pounds with 10% body fat chances are you’re going to lose muscle alarmingly.
(why they’re IFing who knows)
if you’re 250 pounds and 40% body fat then you won’t likely lose any appreciable amount and it’ll be a purely beneficial process(although you will lose some temporarily.
should be viewed on a case by case basis i feel.
You don’t lose appreciable muscle due to catabolism when following an IF protocol under 24hrs. As long as you consume enough protein in your eating window that is.
It is working out brilliantly for me, got my six pack back after many years absence!
J.Stanton,
Are you going to resume your series about the evolution of meat eating? I would enjoy your opinions about the Homo erectus, Homo heidelbergensis and Neanderthals…
Att, Tiago
A fantastic primer, J.S.! This (and no doubt the upcoming articles), will be bookmarked as great go-to articles for people wanting to know more about this topic. Nice work.
anand:
Muscles are indeed our usual store of proteins…but muscle-building is both slow and energetically expensive. Furthermore, our bodies don't “like” to build more muscle than they absolutely have to, because muscle requires substantial energy to maintain even at rest. Thought experiment: how easy is it to gain 20 pounds of lean muscle mass vs. 20 pounds of fat?
You are correct, however, that “muscle memory” appears to be a real phenomenon. I suspect this has to do with the fact that muscles generally grow via hypertrophy, not hyperplasia, but I don't know enough about it to make any definitive pronouncements.
neal matheson:
I don't do well on low-protein diets, either.
marzo:
I'm not sure how I can be biased, seeing as how I haven't made any behavioral recommendations yet.. Care to elaborate?
Miki:
Good point about autophagy: I've oversimplified a little bit by lumping it in with catabolysis in order to keep this article at a finite length. I'll talk about autophagy in more detail in the next installment(s).
Dan Brown:
Yes, I'll be covering glucogenic vs. ketogenic amino acids. In fact, the reason I wrote this was because of a future article involving gluconeogenesis, which was going to involve explaining this subject again in a sidebar!
Asclepius:
I wouldn't hold your breath.
Jason:
Protein combining is obviously a neolithic practice, as hunted and gathered proteins are, in general, complete. Most ancestral cultures simply consumed meat or dairy instead of trying to combine proteins…but there are a few (e.g. Mexicans growing the 'Three Sisters': corn, beans, and squash) who developed the practice without knowing exactly why it worked.
Tony:
Great to hear from you again! I'm not sure how deeply I'll go into the details…part of that depends on how many questions you ask.
vacexempt:
Protein can only be synthesized at a certain rate, and whey is absorbed very quickly. Given that, 90-100g of whey PWO is indeed way too much, and will likely not be fully absorbed by the intestine in order to protect the body from potential toxicity. Result: terrible gas. (And if you're consuming any sort of flavored powder, sucralose is also very likely to contribute to intestinal distress.) 30g immediately PWO, followed by a meal as soon as you can get it, should be fine…anything greater than that is purely for anabolic signaling purposes and not substrate availability (e.g. leucine).
tess:
The review article I linked (Reeds 2000) contains many interesting facts, but no specific mention of tyrosine. I'd have to spend more time looking into it.
Marilyn, Paul, eddie:
You're welcome! And no, I have no idea when the videos of AHS 2012 presentations will be available: first it was “probably two months”, now it's “maybe 4-5 months”. I'm as disappointed as you are, and I encourage anyone who wants to see them sooner to contact the AHS.
More to come!
JS
eddie:
I agree with your restatement of the problem.
However, there are some people who can maintain huge muscle mass on IF (e.g. Martin Berkhan). I can report that it doesn't work for me, though!
johnnyv:
I agree that shorter IFs maintain muscle mass for most. However, a 24-hour IF still involves eating every day…if you skip an entire day of eating, you're at 36 hours or more!
Tiago:
Yes, I'll definitely return to it…though I'm not sure when, as it requires a lot of research and reading.
Jamie:
I'm glad you find it useful. It's easy to forget that most people don't even understand the basics, like “What foods contain protein?” — let alone key details like “Is this protein complete and digestible?”
However, it's also important to remember that this isn't because people are dumb — it's because of the lamentable state of nutrition education.
Meanwhile, if you have any topics or questions you think I should cover in future installments, please let me know!
JS
I agree JS, that building muscles is an energy intensive process. That is why I think weight lifting helps a lot in losing weight. As it causes muscle wear and tear, which requires muscle rebuilding.
I do think that building new muscles takes a lot of time, but building muscles that were there before is a lot easier.
But yes you need to use them to build them. So if you are weight lifting, have enough carbs in the diet for an insulin response, and are in energy surplus, you will rebuild muscles efficiently.
Martin Berkham optimizes several things to avoid adding more fat, by controlling meal times, macronutrients, and supplements like BCAA and whey. With real food it would be difficult (impossible?), at his fat levels.
I also think that very low body fat levels would not be healthy from an evolutionary perspective.
Is there any truth to the idea that when in ketosis junk protein in cells is recycled to meet our protein needs? I’ve seen this stated a lot, but never a reference. If true this could eliminate some of the downside to fasting.
I’m starting to think that Martin Berkhan’s nordic genetic heritage has a lot to do with his “enhanced” or “evolved” ability to “leangain”. I would like to test that on, say, a Hadza hunter, a Kitawan, Italian Toreador, Persian decendant, or Masai warrior (or anyone else whose genetic history is marked by larger ratio of carbs in his diet).
Jozef,
Plenty of carbs have been eaten in scandinavia for several thousand years (by the nordic cultures at least). That said I ma northern European and carbs in excess really make me gain weight.
Thanks for responding. I indeed was trying to cause the anabolic signaling by consuming the extra whey PWO, such as recommended by Ori Hofmekler. I kept simplifying the drink to the point that it’s just plain non-flavored in water, with some cinnamon and vanilla I add, but the high amounts still cause borderline diarrea and frequent trips, not so much gas. Anyhow, it ain’t worth it, I can take the 30 grams without problems. Like I said, at 57, I just want to avoid loosing muscle in a way that’s maintainable as I enter my golden years. Looking forward to the rest of the series!
JS, Vacexempt mentions his “golden years.” I’ve read that people in their golden years process protein less efficiently. Assuming a person is taking no medications that interfere with protein processing, are there other systems that start to fail as one ages? Is eating more protein useful?
Thanks!
anand:
It's unfortunate that muscle synthesis is slow, in addition to being energy-intensive: gaining 20 pounds of lean mass often takes a year of intense training, and is usually only possible for newbies. In contrast, it's easy to gain 20 pounds of fat mass in 2-3 months, simply by stuffing one's face with lots of linoleic acid, gluten grains, and sucrose/HFCS.
I agree that very low bodyfat levels are not a survival trait: fat gives you the ability to survive periods of hunger. There's a reason it's so hard to get under 12% bodyfat (for men): the fat tissue on the belly and “love handles” actually has a slightly different adrenergic receptor, if I recall correctly, and is therefore retained by the body except in extremis. In other words, it's the body's reserve tank, and persuading your body to give it up, while it may get you that coveted “six-pack”, isn't necessarily healthy.
Walter:
You're thinking of autophagy, and it occurs continually. I'll talk more about that subject in future installment(s).
Jozef, neal matheson:
Leangains isn't a VLC protocol, to my knowledge: it involves substantial carb intake on workout days. What I do know is that Martin has is a genetic ability to gain muscle quickly, most likely due to a predominance of Type II muscle fibers. Yes, there are a lot of people who claim to be “hardgainers” because they're lazy: however, nothing will make a person with a predominance of Type I fibers gain muscle the way someone like Martin can. There's a reason the Kalenjin are distance runners, not powerlifters!
vacexempt:
Leucine is the important AA for anabolic signaling: the others just compete for absorption and diminish the impact of leucine, so I think Hofmekler is off base with his recommendation. There are some interesting leucine protocols out there, but you have to be willing to ingest something that tastes like powdered drywall and doesn't mix in water.
Marilyn:
That's too broad a question for me to answer! But yes, more protein can be helpful as one ages…coupled with weightlifting, which will maintain muscle mass as well as bone density (bones wax and wane in proportion to the loads we regularly place on them). The extra protein won't help if your body isn't using it for anything.
JS
I just thought I might point out that for some reason when I type “gnolls.org” at the address bar the page that loads isn’t the newest entry but the “back from AHS” one. I was gonna tell you that after first reading this article yesterday but then I tried it again and it worked normally. Then I tried again today and again it went to the older post, so maybe it’s something on my side but I just thought I’d let you know.
Btw, it’s nice to have you back on these sorts of topics, it’s been a while.
I did some quick testing just now, after accessing this article visiting gnolls.org does take me to it, but clearing the cache reverts it to the AHS post. It’s not really an issue to me, I’m just reporting in case it might not be a problem on my side.
[…] Anyway, for everyone who has questioned the need to eat protein or wondered what you should be eating try this What Is Protein, And Why Do We Need To Eat It Every Day? […]
Fmgd:
It probably has to do with my caching plugin…apparently it (sometimes) forgets to reload the front page when I update. Perhaps I'll switch plugins and see if it helps.
JS
[…] about complexity Dietary protein 101: What is protein, and why do we need to eat it every day? Metabolic syndrome and the teenage brain How many sports are played in Central Park? The way is […]
How much protein do we need? The CW -> paleo amount (50 -> 90 g, depending on gender/size) is probably good for maintenance. The pro need goes way up post- weight-lifting, as the skeletal muscles recover (“recovery’s where you make your gains”). I explain it more here
http://www.jeffreybrauer.blogspot.com/2012/03/how-to-sync-diet-with-exercise.html
@JS
I look forward to more of your take on it, as I look forward to every article in every series here at Gnolls.org.. but then you’ve mind-controlled me with yer subliminal etc. 😛
@vacexempt
“extra” doesn’t necessarily mean 100 g from whey all at once. I find a whey shake of about 50 g is all I can do post-w/o, then a 40 g pro chicken breast w/ romaine lettuce 1-2 hrs after that. So, its 90 g pro, but two meals over 4 hours. HTH..
[…] Dietary Protein 101: What Is Protein, And Why Do We Need To Eat It Every Day? […]
@JS:
Yup, it seems to be working now.
Hi there,
I'm a newbie. Found the site via Free the Animal and have been following ever since. Have not read TGC in whole yet, but have read the preview for free.Already have been Paleo (or mostly Paleo) for over 2 years (going on 3). I've lost and maintained for the most part a 96 pound weight reduction, had no need for allergy medication and reduced my seizure medication by 3/4 in doing so.
I'm still working on the amount of protein I need as well, because I'm beginning to understand that excess protein turns into sugar, which I am trying to avoid, unless it's an Aikido training day.
Thanks again for the great and easy to understand articles and I look forward to the next installment.
Jen W.
@JS:
You are describing the ‘non-instantized’ plain powder I drink. hard to mix, but it’s not so bad with a little vanilla and cinnamon. I’m going to try the 30 g PWO with a meal within 4 hours for the next few workouts. Thanks.
@Jeffery of Troy:
Interesting site; will investigate it more. I was spreading the whey out over the 4 hours PWO, but it was still too much. If I work up to more intense workouts, maybe more will be called for. Taking it slow for now.
Jen W:
Welcome! I wouldn't worry too much about “excess protein turns into sugar”…only a few amino acids are efficient substrates for gluconeogenesis (a topic I'll explore in the future). AFAIK most “excess” aminos tend to be oxidized directly for energy…which is generally ignored in most calculations because it's difficult to measure specifically, but it's a significant route of disposal.
vacexempt:
Plain whey is fine: I have no problem mixing or drinking it straight (just shake it well). Leucine is MUCH worse. Trust me on this.
One of the problems with whey is that it's absorbed VERY quickly…more quickly than your body can absorb or use it if you eat a lot of it. Thus: gas. However, you can eat the equivalent amount of protein in the form of meat with no problem, because it takes much longer to digest and absorb the meat.
I usually only use whey protein immediately PWO. By the time the whey wears off, I've had the time to prepare and eat real food.
JS
Sorry to add this to the comments but I thought you (J) might know the answer to this. I am trying to get hold of bison fat. The Bison farm told me that bison is very lean and contains little fat, visceral or otherwise. Do older bison contain more fat like rabits and deer?
I am painfully aware that virtually all farmed wild meats are marketed as being low fat and wonder whether the low fatness of bison is to do with rearing or slaughter practices.
cheers!
neal:
Bison is leaner on average than beef, but if it's properly raised it'll most definitely accumulate some fat, both subcutaneous and visceral. See this series of pictures.
Fat content depends primarily on the season: assuming they're grazing on native grasses, bison slaughtered in the fall, just before first frost, will be at their fattest because they've been grazing on fresh grass all summer.
JS
Okay thanks for that J
That makes the most sense JS. I've also read(straight from the farm handout at the grocery store) that the same is true of grass-fed cows.
Jen W:
Absolutely. Corn is stored in elevators and is the same year-round, but grass (and hay) are seasonal.
JS
[…] Meal Plan: Pot Roast w/ Pan Gravy, Green Beans & Tomatoes Fighting Depression with CrossFit Why Do We Need To Eat Protein Every Day? Heavy Teens Eat Less But Weigh More Than Their Thinner Peers 5 Exercises Every Woman Should […]
[…] what is protein and why do we need to eat it everyday? recipe sardine roasted garlic […]
Re: Leucine
While it does not dissolve in water, it mixes fine with coconut oil, hardly bothers me at all. In general, those things that don’t dissolve in water may dissolve in oil.
WalterB:
That's good advice. (Unless you're trying to take your leucine while otherwise fasted…)
JS
[…] We always get asked about protein, why we need to it, and how much. Here is a great summary full of answers about […]
[…] Anyway, for everyone who has questioned the need to eat protein or wondered what you should be eating try this What Is Protein, And Why Do We Need To Eat It Every Day? […]
[…] can definitely store fats for a long time and even carbohydrates for a little while, according to J. Stanton at gnolls.org, we don’t store protein. We use it or it gets turned into carbohydrates to be burned or stored, […]
Hey JS, does it matter how much protein you bring in each day to maintain/build muscle?
Brandon:
Yes. I don't know any serious source that recommends less than 1.2g/kg/day for anyone active, and Olympic weightlifters in training can be in negative protein balance at 2g/kg/day!
I've seen the objection that “your body can only build X grams of muscle per day,” but that's silly. Amino acids in the blood aren't just raw materials: some are anabolic signals, particularly leucine.
That being said, chugging 200g+ of whey protein a day is likely to be counterproductive as well as expensive: whey is absorbed so quickly that it's probably not useful to consume more than one scoop at a time. (Or less: I seem to get the same results from a 15-18g serving as a 30g serving.) In contrast, it can take many hours to digest and absorb meat, so it's fine to eat a big steak.
JS
[…] dairy products, we know that milk offers many nutrients, such as calcium (for strong bones!!!) and protein (the building blocks of our body!) And remember, dairy products are animal food products, which […]
[…] http://www.gnolls.org/3224/dietary-protein-101-what-is-protein-and-why-do-we-need-to-eat-it-every-da… […]