ZOE Science & Nutrition - Recap: How much protein do you need? | Prof. Christopher Gardner

Episode Date: November 5, 2024

Did you know you can now buy ice cream with added protein? Even breakfast cereals are jumping on the trend, boasting an extra protein punch. In nearly every supermarket aisle, you'll spot the catchy slogan "high in protein" plastered across packaging. But why is that? Are we not getting enough protein already, or are these high-protein products giving us too much? Our guest is Christopher Gardner, a professor at Stanford University and a member of ZOE’s scientific advisory board, who has published widely on the relationship between protein and our health.  🥑 Make smarter food choices. Become a member a zoe.com - 10% off with code PODCAST 🌱 Try our new plant based wholefood supplement - Daily30+ *Naturally high in copper which contributes to normal energy yielding metabolism and the normal function of the immune system 📚 Books from our ZOE Scientists: The Food For Life Cookbook by Prof. Tim Spector Food For Life by Prof. Tim Spector Every Body Should Know This by Dr Federica Amati Free resources from ZOE: Live Healthier: Top 10 Tips From ZOE Science & Nutrition  Gut Guide - for a healthier microbiome in weeks Have feedback or a topic you'd like us to cover? Let us know here Listen to the full episode on Apple or Spotify

Hello and welcome to Zoey Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're asking the question, how much protein should I eat? From steaks to protein shakes, tofu to high protein ice cream, protein is more available now than ever before. Diets high in protein are associated with staying fuller for longer and become popular with people trying to lose weight. Food manufacturers picked up on this, and today food packaging everywhere

is plastered with a catchy slogan, high in protein. So are we getting too little or too much protein in our modern diet? My guest today is Christopher Gardner, professor at Stanford University and a member of ZOE's Scientific Advisory Board, who's published widely on the relationship between protein and our health. So I have some US data

that shows how much protein people eat, and it's pretty much double, double the RDA. Just eating food, not even trying. And so to me, it's sort of this American idea of, good, let's see, that's what the RDA is, but I know I'm above average. So let me make sure I get some extra here. And it's like, no, you don't understand the concept.

It was built in to recognize that some people would need more. And as a nutritionist, when I teach students, I have to say, this is not an individual approach. You should not look at the RDA to see if you are meeting your individual requirement. This is a population health approach so that everybody were to get that amount. Almost no one would be deficient. And just as you were a bit surprised, every time I tell that story, the audience I explain it to is a little surprised. And so Christopher, you know, I am surprised because I've had this experience and I suspect there's quite a lot of people who have had this experience.

So like the first time I ever went to a gym, which is about 10 years ago, and I had a trainer say, you know, this is what you need to do in order to get healthier, which is what I was interested in and fitter. One of the first thing he said is, oh, well, you need to eat more protein. And you need to eat at least a gram per kilogram of protein if you're going to get, you know, any benefits out of the work that you're going to do at the gym. Now that number, because I think you just said it was 0.8 grams per kilogram, was your recommended amount, which is like the maximum that anyone in the world basically needs. How did this happen? Why is there this controversy? Help me to understand why there's this pressure about feeling people

need to eat more protein. Sure. Okay, so let's think about that. So there are some flaws of this nitrogen balance study that I suggested. And so what happens in at least the US from all the databases I have is, and this is very consistent in all research studies that I look at, Most people get about 16, 17, 18 percent 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 3,000. And I know a lot of your listeners are going to say, not me, I only eat 1,500 calories a day. We've done feeding studies where we gave people a certain amount of calories, and it's really 2,000, 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 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. Okay, so let me tell you how many extra grams of protein you need. So Jonathan, how ambitious would it be to put on 22 pounds or 10 kilos of pure muscle in one year? Would that be pretty good? That I have to say sounds quite ambitious. I think if anybody saw me they would say

totally ridiculous and impossible. But let's go with ambitious, shall we? Okay, ambitious. So 10 kilos. actually 70% of your muscle is water. So if you were gonna do that in a year, all you'd actually have to accumulate is three kilos of extra amino acids or 3,000 grams of extra amino acids. Divide that into 365 days of the year. And just roughly, that means you would need an extra 10 grams of protein

a day to keep, retain, in addition to meeting your maintenance needs to put this on. Now, it's not quite a fair number because when you're in the gym lifting and working out, if you're working out really hard, you're actually breaking down some muscle using those amino acids and you have to replace them. So put another 10 grams on that. Say you needed an extra 20 grams a day every day for a year to put

this on. In the U.S., people are eating like 30 or 40 extra grams a day over that 0.8 gram per kilogram every day just eating food. And one more tidbit I have here is when you're working out hard every day, don't you eat more? You do. You don't eat just 2,000 calories. 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 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 than you needed? What would happen to all that extra, will it kill you to have more protein?

What happens? Okay. So, but I want to 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.

Does my muscles need it? No, I'm doing a podcast with Jonathan. I'm just sitting here. I don't really need my muscles. Okay, well, I have a storage depot for my carbohydrate. It's called glycogen. And there's some in my muscles and there's some in my liver. 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? Any idea? Are you a runner, Jonathan? Actually, I don't know this if you're a runner. No, I'm very good at sitting in my chair doing podcasts, but tell me, how long does it last for?

So 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. Let's switch for a minute to fat. Let's say you ate more fat calories for the day and you used it for various things and mostly you burned it for energy. Where would you store that and how much could you store?

And I'll save you the trouble here. You can store an infinite capacity of 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 fat 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 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 more and you're going to 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? Where is my protein storage? 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. I hope you found the information in this week's episode useful. and fats at the end of the day. Go to zoe.com slash gut guide to download it for free. Or if you're looking for another podcast to listen to, we have a lot more in our back catalog. Would you like to know how to reduce your risk of dementia or how to make the most of coffee's hidden health benefits? Search for these episodes on your favorite podcast player.