Skip to content

The protein prejudices

Die Protein Vorurteile

I was in the lab yesterday, playing researcher, when an aggressive and confident undergraduate student burst in through an unlocked door.

"Excuse me, is there anyone here I can talk to about protein?"

Since the sign on the outside of our door reads "University of Western Ontario, Exercise Nutrition Lab," it's pretty obvious to everyone that this is an exercise and nutrition counseling office that is only concerned with giving anyone who barges in unasked all the answers to their questions right then and there.

"I guess that's me" I replied shyly, fearing what was to come. "What would you like to know about protein?"

"My question is this: Why do all the magazines say that athletes need more protein when it's clear that they don't?"

Take a deep breath...

Rather than start a discussion with him, I simply wrote him the name of the weight training and nutrition site on the internet that I occasionally write articles for on a scrap of paper and sent him away. I have long since given up on the idea that I could somehow change the wrong nutritional ideas in front of anyone. When I get into a situation like this, I try not to get carried away into a full-blown nutritional tirade highlighting the fact that arrogance and ignorance should not be combined together in one meal. Or was that protein and carbs? I can never remember.

Instead, I usually try to remind myself that at some point along the way, each of us has asked the most famous protein question of all: "How much protein do athletes need?" And at some point, despite our initial preconceptions, we all learn that athletes should probably eat more protein than their sedentary counterparts.

Unfortunately, many simply believe that just because Dr. Lemon said so, they should just eat 1.6 to 2 grams of protein per kilogram of body mass and be done with it.

After correcting their protein intake in this way, these people usually don't give their protein intake a second thought until the time comes to chastise these ignorant simpletons who eat less protein. But can correcting our protein intake be as easy as so many believe?

Personally, I don't think so. And that's what this article is all about - figuring out the difference between protein needs and optimal protein intake. Ultimately, in this article I will convince you that athletes might actually need less protein than sedentary people. That's right, I said "less". In addition to this, I will convince you that even if athletes actually need less protein than sedentary people, they should still eat more protein - a lot more.

Need vs. optimization

Let's take a moment and examine the most commonly asked protein question addressed above - How much protein does an athlete need?

When someone asks this question, they are usually trying to figure out how much protein the athlete in question should eat to optimize their body composition and athletic performance. But the question "How much protein does an athlete need" is very different from "How much protein should an athlete eat to improve their body composition and athletic performance?" It is therefore important to differentiate between what someone needs and what is optimal.

In the realm of science, the word "need" has no relationship to optimization. Instead, it is defined as the minimum amount needed to prevent deficiency. Therefore, when you ask how much protein an athlete needs, you are really asking "What is the minimum amount of protein an athlete can get away with to prevent physical decline and death?"

Since most athletes have access to enough protein and usually consume enough protein to prevent death and decline, the common question of how much protein an athlete needs is a bad question. This question does not address the issue that really matters - the question of what an athlete should consume to improve performance and body composition.

Do athletes need more protein?

While it's obvious that the question of protein needs is purely academic, I want to address it here because the answer will probably shock you.

Before we talk about specific numbers, I need to give you some background on how protein requirements can be measured. Measuring the protein requirements of different populations is usually achieved using the nitrogen balance technique. This technique involves measuring the amount of nitrogen consumed (protein sources) and the amount of nitrogen excreted in urine, sweat and feces.

If the amount of nitrogen entering your body is higher than the amount of nitrogen leaving your body, then we speak of a positive nitrogen balance or positive nitrogen status. In this case, it is assumed that the excess protein retained by the body has been used to build body tissue.

If the amount of nitrogen supplied is equal to the amount of nitrogen excreted, then we speak of a balanced nitrogen balance. In this case, it is assumed that the person in question eats just enough protein to prevent a deficiency, but not enough to build additional body tissue.

If the amount of nitrogen entering the body is less than the amount of nitrogen leaving the body, this is called a negative nitrogen balance. In this case, it is assumed that the person in question is suffering from a protein deficiency and that the body will initially break down muscle tissue and ultimately organ mass in order to ensure its basic supply of amino acids.

It is therefore important to recognize that most studies on protein requirements look for the amount of protein at which a person is nitrogen balanced - or the amount of protein that is just enough to prevent protein deficiency.

Based on the results of these nitrogen balance experiments, it was recommended that untrained individuals should consume 0.8 grams of protein per kilogram of body mass to meet their needs. And to reiterate, this is the amount of protein needed to keep their nitrogen balance in balance while preventing a dreaded negative nitrogen balance (which can lead to protein malnutrition, muscle and organ breakdown and ultimately death).

As for the needs of athletes, the work of Lemon, Tarnopolsky and colleagues has provided some evidence that athletes need more protein (Lemon et al 1981, Tarnopolsky et al 1988, Tarmonpolsky et al 1992, Lemon et al 1997). This classic research suggests that during intense training, strength and endurance athletes need protein in the range of 1.4 to 2 grams per kilogram of body mass to maintain a neutral nitrogen balance.

But what about all the athletes and weightlifters out there who consume less protein than the recommended 1.4 to 2 grams per kilogram of body mass? If they really needed those 1.4 to 2 grams per kilogram of body mass, wouldn't they suffer from physical deterioration and die? Since this is not the case, it cannot be that they need all this protein. So what's the deal?

As Rennie and colleagues have pointed out, there are several problems with trying to apply Lemon and Tarnoposky's data to recreational and casual athletes. First of all, Lemon and Tarnoposky's studies were conducted with athletes who were following training programs that were new to them.

Even if the subjects were physically active before the study began, the training stimulus (strength training in some studies, endurance training in others) was new to them, which almost certainly resulted in a short-term increase in protein requirements - an increase that is not sustained over the long term (Rennie et al 1999, 2000). In other words, Rennie argues that although a new training program (whether strength or endurance training) may result in an acute increase in protein requirements, chronic training is unlikely to increase protein requirements at all.

Now before you start hating Rennie, it's important to understand that this guy is a legend in the field of protein research. Type his name into Medline and you'll find several hundred protein-related research publications. Aside from his excellent reputation, his ideas have both theoretical and investigational support.

In particular, research by Butterfield and colleagues suggests that athletes may actually need less protein due to increased protein efficiency that may accompany chronic training (Butterfield and Calloway 1984). In other words, this means that athletes may become more efficient in their protein use (i.e., increased anabolic efficiency) and therefore may require less than the 0.8 grams of protein per kilogram of body weight required by sedentary people!

Is this Rennie guy crazy? Probably not. And why do his statements contradict everything athletes and weightlifters know - namely that a higher protein diet helps build muscle mass and promote a more desirable body composition? Well, in truth, these statements don't really contradict the experiences of athletes. If you think this, then you haven't been paying attention to what we talked about earlier - i.e. you're still confusing need and optimization.

An athlete may need less protein to stay alive, but they should consume more protein to optimize performance and body composition. So when I am asked how much protein an athlete needs, my best answer is that it doesn't matter! Asking how much protein an athlete needs is like asking how much a student needs to study for an exam. Since a student only needs to pass their exam to remain a student, the correct answer would be "as much as is necessary to answer more than 60% of the questions correctly." However, very few students will only want to achieve this low score. Therefore, the best question would be "How much does a student need to study to ace their exam?"

Optimizing protein intake

In the section above, I suggested that athletes may actually need less protein per day than the typical dose of 0.8 grams per kilogram of body weight that is considered the minimum for physically inactive people. The Butterfield study even gives an exact figure for this: 0.65 grams of protein per kilogram of body weight.

Using this figure to calculate the exact amount of protein needed to maintain a neutral nitrogen balance, a 90 kilogram athlete would need around 60 grams of protein per day to prevent muscle breakdown and protein malnutrition.

So those who still strictly believe that they only need to eat enough protein to meet their needs can reduce their protein intake from 2 grams to 0.65 grams per kilogram of body weight from now on. In the meantime, I will encourage everyone else to increase their protein intake even beyond the current recommendation of 2 grams of protein per kilogram of body weight.

If this recommendation seems excessive, it's because you have too narrow a view of how protein fits into your dietary strategy. You're looking at protein from the same narrow perspective that people used to look at vitamin C - essential at a specific dosage, but with no added benefit at a higher dosage.

With vitamin C, we all know how important it is to consume enough of it (at least 10 mg per day) to prevent scurvy. However, it is also widely known that there are a variety of health benefits to consuming larger amounts of vitamin C (200 mg per day or more), including an increase in good HDL cholesterol levels, a reduced risk of coronary artery disease and a reduction in the symptoms and duration of the common cold.

As with vitamin C, if we stop thinking of protein as a macronutrient with no benefits other than preventing protein deficiency, we can see numerous benefits of consuming protein (in any dose). These include the following benefits

Increased thermic effect of food

Although all macronutrients require metabolic processing for digestion, absorption and storage or oxidation, the thermic effect of protein is roughly twice as strong as that of carbohydrates and fat. Therefore, the consumption of protein is thermogenic and can lead to a higher metabolic rate. This means increased fat loss during a diet and less fat build-up in the event of a calorie surplus.

Increased glucagon levels

Protein consumption increases the plasma concentrations of the hormone glucagon. Glucagon has the opposite effect of insulin in adipose tissue, which results in increased mobilization of body fat. In addition to this, glucagon also reduces the quantity and activity of the enzymes responsible for the build-up of adipose tissue and the storage of fat in adipose tissue and liver cells. This also leads to increased fat loss during a diet and less fat storage in the case of excessive calorie intake.

Increased IGF-1 levels

Protein and amino acid supplementation has been shown to increase the IGF-1 response to both exercise and food intake. Since IGF-1 is an anabolic hormone associated with muscle growth, another benefit associated with higher protein consumption is increased muscle growth in the event of a calorie surplus and a muscle-protective effect during a calorie-restricted diet.

A reduction in the risk of cardiovascular disease

Several studies have shown that increasing the percentage of protein intake in the diet (from 11 to 23%) while reducing the percentage of carbohydrates (from 63 to 48%) lowers LDL cholesterol levels and triglyceride levels while increasing good HDL cholesterol levels.

Improved weight loss profile

Groundbreaking new research by Layman and colleagues has shown that reducing the carbohydrate ratio from 3.5 to 1.4 to 1 increases body fat loss, protects against muscle breakdown, lowers triglyceride levels, improves satiety and improves glycemic control. (Layman et al 2003 - If you are interested in protein intake, then you need to read the January and February 2003 issues of the Journal of Nutrition. These contain three interesting articles by Layman).

Increased protein turnover

As I described in an earlier article, all tissues in the body, including muscle tissue, go through a regular renewal process. Since the ratio of protein breakdown to protein synthesis determines protein turnover, you need to increase your protein turnover rates to improve your muscle quality the most. A high protein intake does just that. By increasing both protein synthesis and protein breakdown, a high protein diet will help you get rid of old muscle tissue faster and build new, more functional muscle to replace that old muscle tissue.

A more positive nitrogen balance

I have already explained in one of the previous sections that a positive nitrogen balance means that more protein enters the body than protein leaves the body. High protein diets create a more positive nitrogen balance and when this increased protein availability is combined with a training program that increases the body's anabolic efficiency, the growth process of muscle tissue is also accelerated.

Increased availability of additional nutrients

Although the benefits mentioned above are specifically related to protein and amino acids, it is important to recognize that we don't just eat protein and amino acids - we eat food. Therefore, high-protein diets often also provide additional nutrients that can promote performance and/or muscle growth. These nutrients include creatine, branched-chain amino acids, conjugated linoleic acid and/or additional nutrients that are important but have not yet been discovered. This highlights the need to consume protein in the form of food and not just supplements.

Looking at the list of benefits, it is clear that consuming plenty of protein is beneficial to any athlete's training goals. Since a high protein diet can lead to a better health profile, increased metabolic rate, better body composition and improved training response, it makes no sense whatsoever to ever try to limit protein intake to the bare minimum necessary to prevent malnutrition.

In my opinion, protein is the nutrient that you should consume too much of rather than too little, regardless of whether you are on a calorie restricted diet or a calorie surplus. Instead, the bias against protein leads most exercisers to consume the amount of protein they consider to be the bare minimum and instead consume too many carbohydrates and too much fat. This is a big mistake in terms of performance and body composition.

I have yet to meet a healthy man or woman who couldn't have done with a little more protein in their diet. It's time we rethink our preconceptions about protein and start giving this macronutrient the respect it deserves.

Now get out of my lab - I have work to do and you need to eat some protein.


By John Berardi, PhD

Previous article 12 healthy foods that are rich in antioxidants