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

Summary

ZOE Science & Nutrition Podcast Summary

Episode Title: Recap: How Much Protein Do You Need? | Prof. Christopher Gardner
Host: Jonathan Wolf
Guest: Prof. Christopher Gardner, Stanford University
Release Date: November 5, 2024

Introduction

In this enlightening episode of ZOE Science & Nutrition, host Jonathan Wolf delves into the pervasive question: How much protein should I eat? With protein-backed products dominating grocery shelves—from steaks and tofu to protein shakes and high-protein ice creams—the topic has never been more relevant. To shed light on this, Jonathan welcomes Prof. Christopher Gardner, a renowned nutrition expert and member of ZOE's scientific advisory board, to discuss the intricacies of protein consumption and its impact on health and weight management.

Understanding Protein Requirements

Prof. Gardner opens the conversation by highlighting a startling statistic: average American protein intake is nearly double the Recommended Dietary Allowance (RDA). He shares, “[B: 00:59] 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.” This revelation challenges the common perception that individuals need to consciously increase their protein intake to meet their dietary needs.

The RDA Explained

Jonathan and Prof. Gardner discuss the fundamental purpose of the RDA. Prof. Gardner clarifies, “[B: 00:59] 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.” The RDA is designed as a population health guideline to ensure that nearly everyone meets their nutritional needs, rather than serving as a personalized metric. This distinction often leads to misunderstandings, particularly in fitness communities where individualized protein needs are emphasized.

Protein Consumption in the US

Prof. Gardner presents data from various US nutritional databases, consistently showing that most Americans derive 16-18% of their daily calories from protein, translating to approximately 1.5 grams of protein per kilogram of body weight without deliberate effort. He elaborates, “[B: 02:49] People are eating like 30 or 40 extra grams a day over that 0.8 gram per kilogram every day, just eating food.” This intake surpasses the RDA of 0.8 grams per kilogram, indicating that the average diet already provides ample protein for general health without the necessity for intentional increase.

Protein and Fitness Goals

The conversation shifts to protein intake in the context of fitness and muscle building. Jonathan recalls advice from a personal trainer to consume at least 1 gram of protein per kilogram of body weight to maximize gym efforts. Prof. Gardner addresses this by explaining the additional protein required for muscle synthesis. “[B: 04:32] 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?” He breaks down the actual protein needs, demonstrating that to gain 10 kilograms of muscle, one would require an extra 10-20 grams of protein per day. This is significantly lower than what many consume, as Prof. Gardner notes, “[B: 04:42] In the US people are eating like 30 or 40 extra grams a day over that 0.8 gram per kilogram every day, just eating food.”

Metabolism of Excess Protein

A critical point in the discussion is what happens to excess protein that the body doesn't need. Prof. Gardner elucidates, “[B: 08:36] Every bit of it at the end of the day has the nitrogen taken off and it gets turned into carbs and fats. You can't store protein in your body.” Unlike carbohydrates and fats, the body lacks a storage mechanism for protein. Consequently, surplus protein is converted into carbohydrates and fats, potentially contributing to weight gain if consumed in excess. He emphasizes, “[B: 08:34] So where do you put it in your body? ... You're turning all that into carbs and fats at the end of the day.”

Implications for Health and Diet

The episode underscores the importance of understanding protein needs in relation to overall diet and lifestyle. While high-protein diets can aid in satiety and weight management, Prof. Gardner cautions against overconsumption. He draws parallels to carbohydrate and fat storage, explaining that while carbohydrate storage (glycogen) is limited and fat storage is virtually unlimited, protein has no such storage pathway. This metabolic pathway highlights the necessity of balancing protein intake to avoid unnecessary conversion to fat.

Key Takeaways

Average Protein Intake: Most Americans consume approximately 1.5 grams of protein per kilogram of body weight, which is nearly double the RDA of 0.8 grams per kilogram.
RDA vs. Individual Needs: The RDA serves as a population guideline, not an individual requirement. Personalized protein needs may vary based on activity level, health goals, and other factors.
Muscle Building Requirements: To gain muscle mass, an additional 10-20 grams of protein per day may be sufficient, which is often less than what individuals consume unintentionally.
Metabolic Processing of Excess Protein: The body cannot store protein, leading to its conversion into carbohydrates and fats when consumed in excess.
Balanced Diet Emphasis: Understanding the balance of macronutrients is crucial for effective health and weight management, avoiding the pitfalls of overconsumption of any single macronutrient.

Notable Quotes

Prof. Christopher Gardner [00:59]:
“The RDA was built in to recognize that some people would need more. And as a nutritionist... this is not an individual approach.”
Prof. Christopher Gardner [02:49]:
“People are eating like 30 or 40 extra grams a day over that 0.8 gram per kilogram every day, just eating food.”
Prof. Christopher Gardner [08:36]:
“Every bit of it at the end of the day has the nitrogen taken off and it gets turned into carbs and fats. You can't store protein in your body.”

Conclusion

This episode of ZOE Science & Nutrition offers a comprehensive exploration of protein intake, debunking common myths and providing science-backed insights into optimal consumption levels. By understanding the distinction between population guidelines and individual needs, and recognizing the body's metabolic pathways for excess protein, listeners are better equipped to make informed dietary choices that align with their health and fitness goals.

For more expert discussions and practical health advice, join ZOE's membership and stay updated by following ZOE Science & Nutrition on your preferred podcast platform.

Transcript

A (0:01)

Hello and welcome to Zoe 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.

B (0:59)

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, God, 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. 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 if 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.

A (1:54)

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've 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 things 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 any benefit 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.

B (2:49)

Sure. Okay, so let's think about that was. So there is, 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, this is very consistent. In all research studies that I look at, 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 3,000. And I know a lot of your listeners are going to 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, 20, 500 or 3000. 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, 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?