Everything you thought you knew about protein is wrong

Ideally, if you have 48 non-ADHD minutes, you should watch this Zoe interview of Stanford professor Christopher Gardner. But if you don’t have that kind of time or, like me, are more of a text person, this post summarises key takeaways. Gardner is the Director of Nutrition Studies at Stanford University, one of the world’s leading nutritional researchers, and the lead author of a peer reviewed paper on recommended protein intake in nutrition.

Fundamental Protein Facts

Protein is primarily structural in our body (unlike fats and carbs which are fuel)
Proteins make up our cells, organs, hair, fingernails, enzymes, and many hormones
All proteins are made from 20 amino acids, which function like “letters” that form different “words”
Our body completely breaks down proteins into individual amino acids during digestion, then reassembles them

Protein Requirements

Most people eat about double the protein they actually need (typically 1.5g/kg vs 0.8g/kg recommended)
The RDA (0.8g/kg) was intentionally set high to cover 97.5% of the population’s needs
Athletes may need slightly more protein (up to 1.6g/kg), but most already consume this amount without trying
To build 10kg of muscle in a year would only require an extra 10-20g of protein daily

Excess Protein Myths

You cannot store excess protein in your body
Excess protein is broken down - the nitrogen is removed and excreted, while the rest is converted to carbs and fat
Protein supplements, shakes, and bars are largely unnecessary for most people
Most excess protein ultimately gets converted to body fat when not needed

Plant vs. Animal Protein

All 20 amino acids exist in all plant foods (major myth debunked)
Plant proteins have slightly different proportions of amino acids compared to animal proteins
After the body digests protein (which is ‘breaking them down’ into their single amino acid levels and reassembles them), it has no memory of where the protein came from!
Plants have slightly lower amounts of lysine and methionine relatively, but since most people eat excess protein, this is irrelevant
Beans, legumes, and whole grains provide excellent protein sources with added benefits of fiber, antioxidants, and phytochemicals

Special Considerations

Growing children, pregnant women, and some elderly people may have slightly higher protein needs
For elderly people with reduced appetite, ensuring protein-rich foods may be important
Most people eating a varied diet, including vegans and vegetarians, easily meet their protein requirements

Best Protein Sources

Beans and legumes are recommended as the healthiest protein sources
They’re nutritious, inexpensive, sustainable, and come with fiber and phytochemicals
Athletes and active individuals can meet all their protein needs with plant sources

The bottom line: Most people are consuming more than enough protein and don’t need to worry about getting more. Protein supplements and marketing claims about “high protein” are largely unnecessary and potentially misleading.

Below is a subset of the transcript that I found most educational (CG = Chris Gardner, JW = Jonathan Wolf, founder & CEO of the Zoe podcast).

[JW] What is protein and why do we need it?

[CG] So when it comes to fat and carb, that’s really most of our fuel. When it comes to protein, it’s more of our structure. So all of our cells and our organs and our hair and our fingernails, all of that is structural protein. All the enzymes that are in our body that catalyze reactions and make, uh, metabolism move forward, those are all proteins. Many hormones are proteins. There’s actually a huge list of functional things that proteins do and to take it to one next level, maybe this is helpful, maybe this is not, all proteins are made of 20 amino acids in the human body, and I like to think of them like Scrabble letters in the Scrabble board game or the letter somebody would put on the marquee of a movie theater. And for perspective, there’s a couple of them that are only three amino acids tied together, which would be called a tripeptide, but that would be unusual. The largest one I know of is something called maybe Tintin, it’s 35,000 amino acids strung together, in a specific chain.

[CG] One could be a limerick, you know, and one could be a haiku. It’s just amazing how they differ in length. And what’s critical is not only that, the specific amino acids one after another be perfect. Like if you were spell checking your, you’re writing in a document and would say, Nope, that word doesn’t work. So it has to be perfect. And then when the amino acids are arranged in a certain, um, configuration. These long strings of amino acids, uh, twirl and twist and conform, they actually have to be side by side in just the right way. And if you change that and unravel them, which happens in your stomach with a low pH, it happens with heat, you inactivate the protein. And if it was going to have some functional purpose, like an enzyme or a hormone, it no longer works. And now it’s kind of just like fuel. Now you can just break apart the single amino acids and use them, but it can’t function like it was going to. And that’s why protein’s so tricky. So many things that it does so many ways to activate and inactivate it.

[JW] You’re basically saying, you know, we eat food with proteins in it, we break it down. There are like 20 of the potential like building blocks, like letters, which is what you’re calling these amino acids. And then our body makes almost everything we are made of out of those like 20 letters in unimaginably complex sort of combinations.

[CG] I like the way you said that. And let me add one twist to this, which is pretty interesting. There’s very few rare exceptions to this, but when you say eat an animal protein or a plant protein and it goes into your digestive tract, you can’t absorb those amino acids into your body until you break them down to their single amino acid levels and then you absorb them, travels through your body, reassembles them, can’t remember where it came from. Oh, did this come from? Oh, did this come from a pig? Oh, did this come from broccoli? No clue. It’s like, oh, it’s just this amino acid. I don’t even care. It came from a supplement. Can’t even tell. It’s just the building block.

[JW] Um, you are saying there are these 20 amino acids, actually we can make some of them ourselves, but actually like, I think you were saying nine of them, we can’t make them. So you, you’ve gotta eat them. Right?

[CG] That’s correct.

[JW] So how much protein do we need to get into our bodies?

[CG] I’m gonna take one big step back and say if you’ve eaten enough calories for the day, you’ve got enough protein. Just so stop obsessing about protein, protein is in everything. All 20 amino acids are in all plant foods, big myth to bust here, and all animal foods. So if you’re simply getting enough calories with a reasonable variety in your diet, like if you only ate rice all day, you wouldn’t get enough. If you only ate cassava all day, you wouldn’t get enough protein, but you also wouldn’t get a lot, you also wouldn’t get enough of other nutrients.

[JW] You’re saying that when they came up with a recommended amount for protein - EAR (Estimated Average Requirement) - they basically picked the amount to make sure that almost nobody would have too little.

[CG] Yes because the underlying study that determined people’s protein needs, it was a normal distribution curve - which means that some people needed very little, some people need a lot. So when the US comes up with recommended daily allowances for protein, vitamins, and minerals, the standard approaches to take two standard deviations above the average, and in mathematical terms, that means you’ve picked a number that should be adequate for 97 and a half percent of the population, and there might be a couple people in the tail that need even higher than that. So if really everybody in the US or the UK, wherever got exactly that, 97 and a half percent, two standard deviations higher, how many would be exceeding their requirement? Oh, actually like 97%, now 97.

[CG] Most people get about 16, 17, 18% of their calories from protein. It’s so consistent. It’s just amazing. And then you look at how many calories you eat to maintain your weight, and let’s not go down this rabbit hole, but most people underestimate how many calories they eat. The data I have says women eat 2,500 calories a day and men eat 3000. And I know a lot of your listeners are gonna say, not me. I only eat 1500 calories a day. We’ve done feeding studies where we gave people a certain amount of calories and it’s really 2000, 2,500 or 3,000. If you take 16, 17, 18% of those numbers, people tend to get about 1.5 grams of protein per kilogram body weight. Without trying, they’re, they’re pretty much getting double the RDA. So now here’s what happens if you’re in the gym getting that double the RDA, right? Okay, so it’s probably the 0.8 grams per kilogram met your need for enzymes, hormones, fingernails and hair. You went to the gym to lift weights and gain muscle. So you probably want more than 0.8 grams per kilogram per day. So you can put muscle on.

[CG] I have a Stanford football player who was in one of the Rose Bowl games. He was eating 5,000 calories a day, because they work him so hard. He was getting 260 grams of protein every day without trying, he wasn’t having shakes, he was just having food. So we, we should go to like, which foods have that protein, but if we could go here, I have one more place to go is well wait. Is that bad? What if you actually got more protein? , then you needed. What, what would happen to all that extra? But will it kill you to have more protein?

[CG] Okay, so, but I wanna go down a rabbit hole just for a minute for a fun exercise. So think on an average day, you probably eat more carbohydrates than you need. And so once you’ve eaten some carbohydrate, the first thing it says, oh my God, does my brain need it right now? Nope. My brain’s okay. Um, do I, does my, do I my muscles need it? No. I don’t really need my muscles. Okay. I have a storage depot for my carbohydrate, and it’s called glycogen. So I will try to fill up my storage capacity of glycogen stored carbohydrate so that I can have some later in the day. And do you know how long it would take you to deplete all the storage carbohydrate in your body? I bet you’ve heard that marathon runners at 20 miles bonk, if they don’t have enough carbohydrate, that basically means you’ve used up all the glycogen that you stored in your body. It’s only about a kilo. Okay, let’s switch for a minute. To fat. Oh my gosh. You can store hundreds and hundreds and hundreds of pounds of fat in your butt, in your thighs, in your jowls, in the pads, in your fingers. Endless capacity to store fat. It would take you an incredibly long time to use up all the storage of. that you have in your body. So unlimited capacity to store fat, a very limited capacity to store carbohydrate. Where could the extra protein go? So your, your trainer told you to do this. You ate all that extra protein. You made your enzymes, you made your hormones, you lifted your weights, and it was a little more than you needed, or maybe a lot. and you’re gonna bed tonight. So where do you think you put it in your body? Is it in your spleen, in your liver, in your big toe, in your elbow? Where’s your protein storage?

[JW] Where is my protein storage?

[CG] None. Every bit of it at the end of the day has the nitrogen taken off and it gets turned into carbs and fat. You can’t store protein. In your body. So the muscle heads who are having a lot of meat and regular meals and a protein shake and a protein bar are turning all that into carbs and fats at the end of the day.

And yet, the nitrogen will be taken off, your liver will turn it into ammonia, and your kidney will excrete it and get it outta your body. And so you actually could suck out some calcium as it goes. And so some people say, don’t eat too much protein. It’ll suck the calcium outta your bones. Let’s not go down that rabbit hole. It probably doesn’t happen. Most people with a healthy kidney can eliminate this just fine. You, you might know that if someone has an impaired kidney, one of the first things they do from a dietary perspective is they ask them to limit their protein. Because they don’t want their, their impaired kidney to face the challenge of clearing more of this excess ammonia from the excess protein that most people get in a day. But to be honest, most people’s bodies are set up to handle this, turn into carbon fat and get rid of the ammonia for, so for most people, eating that protein isn’t necessarily bad for you unless you consider what came with it.