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How much protein does an endurance athlete really need?


The Protein Spectrum for Endurance Sport

By Eric Helms, MPhil, MS, CSCS, NASM FNS & PES

I’ve looked up to my cousin Josh since I was young. Whether he’s known it or not, he modelled values and behaviours that are now part of my life code. In my eyes, he’s a man of integrity and passion and it’s no wonder he’s successful. For Josh, personal growth is always on the horizon and he’s confident yet he continually humbles himself to learn new things. Thus, when he asked me to write a guest blog, I was deeply honoured.

Josh and I have had different life experiences to get where we are today, but we’ve landed in similar spots. He’s a nutritional consultant for endurance athletes (among other things), and I’m a consultant for strength athletes (among other things). I’ve spent a decade training myself, competing as a strength athlete, training other competitors, and learning exercise science and nutritional science in the classroom, the lab, and in the field. I can tell you that if there is one nutritional topic that is discussed ad nauseam by strength athletes, it is protein intake. In fact, it’s of so much interest to strength athletes that I did my master’s thesis on the topic. However, it’s often glossed over in the nutritional discussions of endurance athletes. Considering just how important fuelling endurance training is (which isn’t the primary role of dietary protein), this is understandable. Rightly so, the discussion of protein tends to play second fiddle to hydration, electrolytes, dietary fat and carbohydrate.

It’s true that determining best practices for glycogen loading, in-race fuelling, electrolyte and fluid consumption, fat adaptation, ultra-endurance fuelling and dietary supplementation all can have a direct impact on performance. However, that doesn’t mean these are the only topics of import. Discussing these concepts without any mention of muscular repair, adaptation and recovery is like spending all your money on the best fuel possible for a race car without saving any cash to get its oil changed. Yes, you must fuel your engine but you’ve also got to make sure the engine itself is maintained.

The vast majority of our body is made up of proteins and for athletes protein serves a variety of roles supporting everything from immune function [1], to muscle mass retention during weight loss [2], to muscle gain while weight training [3], to controlling hunger while dieting [4]. The majority of our daily activity is fuelled by the metabolism of fat and carbohydrate, but a small portion comes from protein. Thus, unlike strength athletes who simply benefit from an increased protein intake to assist their adaptations to training [3], endurance athletes actually require a higher protein intake to match their very high energy expenditures [5]. Additionally, endurance training increases amounts of mitochondrial enzymes, haemoglobin, myoglobin and capillaries and these processes may benefit from an increased protein intake as well [6].

But how much is “an increased intake”? Well, this depends on the energy intake of the athlete, the body composition of the athlete, their total training volume and whether or not they are trying to lose weight or reduce their body fat [5, 7]. The daily recommended protein intake for a sedentary non athlete is only ~.4g/lb per day. However, highly active individuals and athletes need more [5]. During a moderate volume training cycle, an endurance athlete who is not over-fat will do just fine consuming .5-.6g/lbs of protein daily [5, 6]. When a high volume cycle of training is being performed, closer to .7g/lbs may be more appropriate [8]. However, when calories are being restricted needs increase as well. Researchers in one study found that runners eating slightly less than their daily caloric needs while clocking 5 to 10 miles per day, found themselves losing body protein even while consuming .9g/lbs of protein [9]! Additionally, the leaner someone is the more likely they are to utilize body proteins for fuel [10, 11] and this becomes more pronounced when inadequate calories are consumed [12]. Thus, while .5-.7g/lbs of protein per day will cover the protein needs of the average endurance athlete during all phases of training, if the athlete in question is also restricting calories (perhaps to lose weight or improve body composition), an intake closer to 1g/lbs may be appropriate until the calorie restricted period is over [9]. Finally, because body composition, training volume, diet and other factors each affect protein needs, there is a great deal of individual variation in protein requirements. One study on female cyclists during a high volume block of training found that on average a protein intake of .7g/lbs per day was required to meet needs, however one individual required 1.3g/lbs [8]!

Protein needs are proportionate to lean body mass as this is the compartment they affect, thus part of the reason why such disparate needs exist between athletes is the large differences in body composition between individuals. For example, males naturally have lower levels of body fat while females physiologically have higher levels. A survey of elite athletes uncovered that male distance runners on average have a body fat percentage of ~8% while elite female distance runners have a body fat percentage of ~17% [13]. Thus, assigning a protein intake based on total body weight can lead one astray as it doesn’t account for how much of your weight is fat versus lean mass. A simple method of dealing with this, is to assign protein intake based on lean body mass in order to make a more accurate individual recommendation [7].

The take home message from all of this is that there isn’t one magic number to follow that will satisfy your protein needs as an endurance athlete. More than likely, there is a spectrum that you will fall somewhere along depending on your diet, body composition and training volume at any given time. To better define this range for the individual, think of the following as conditions that will increase the amount of protein you should consume:

  • Performing a high volume training cycle

  • Eating inadequate calories or losing weight

  • Highly active lifestyle outside of training

  • Below 15% body fat for males or 25% body fat for females

  • Tendency to overeat due to hunger

Then, consider the following as conditions that will decrease the amount of protein you should consume:

  • Performing a low volume training cycle

  • Eating a caloric surplus and gaining weight

  • Inactive lifestyle outside of training

  • Above 15% body fat for males or 25% body fat for females

  • Tendency to feel full and under eat

Once you have established what might be driving your ideal protein intake up or down, place yourself on the spectrum of .6-1.4g of protein per day per pound of lean body mass. Remember, this is your lean body mass not your total body mass. Thus, you must know your body fat percentage with some degree of accuracy first. If you don’t know it, simply decrease the upper and lower end of the range by .1g (so use .5-1.3g/lbs of total body mass if body fat percentage is unknown).

For example, if you are 175lbs at 14% body fat, that means you have 150lbs of lean body mass (86% of 175lbs). Thus, your intake range falls between 90-210g of protein per day. Does that seem like a broad range? It is! However, there is a big difference between a male office worker at 20% body fat with a tendency to overeat who does casual endurance training, and a female professional athlete that teaches group exercise classes dieting down from 18% body fat to 15% in preparation for a race. The latter should probably have her protein intake in the range of 1-1.4g per pound of lean body mass, while the former gentleman would do just fine consuming .6g per pound of lean body mass. However, if he struggles with overeating he might benefit from the hunger blunting effects of a higher protein diet…so as you can see it’s not all physiological, the behavioural side of things can’t be ignored.

To summarize, while fuelling your races and your training is incredibly important, you also have to be aware of the importance of repair and recovery. The combined effects of your training volume, body composition, hunger levels and caloric intake should determine your protein intake. Based on these variables, place yourself somewhere along the spectrum of .6-1.4g protein per day per pound of lean body mass, or if you don’t know your lean body mass, along the spectrum of .5-1.3g protein per day per pound of total body mass. As your training, nutrition, behaviour and body changes, so too should your protein intake. So eat up, train hard, and watch your performance improve!

Eric Helms is a co-owner of 3D Muscle Journey. 3DMJ is dedicated to providing evidence-based information, community support, and holistic coaching to drug-free lifters. He’s coached hundreds of athletes, attained professional status with the INBA and competed internationally in raw-powerlifting with the IPF. He holds two masters; in exercise science and also nutrition for physique and strength sport. He is pursuing his PhD researching auto-regulation in powerlifting at AUT in New Zealand. He also happens to be one awesome dude.

You can see more of Eric's work here:



1. Campbell, B., et al., International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition, 2007. 4(1): p. 8.

2. Mettler, S., N. Mitchell, and K.D. Tipton, Increased protein intake reduces lean body mass loss during weight loss in athletes. Medicine and Science in Sports and Exercise, 2010. 42(2): p. 326-37.

3. Phillips, S.M. and L.J. Van Loon, Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci, 2011. 29 Suppl 1: p. S29-38.

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5. Lemon, P.W., Beyond the zone: Protein needs of active individuals. Journal of the American College of Nutrition, 2000. 19(suppl 5): p. 513S-21S.

6. Tarnopolsky, M., Protein requirements for endurance athletes. Nutrition, 2004. 20(7-8): p. 662-8.

7. Helms, E.R., et al., A Systematic Review of Dietary Protein During Caloric Restriction in Resistance Trained Lean Athletes: A Case for Higher Intakes. International Journal of Sport Nutrition and Exercise Metabolism, 2014. 24(2).

8. Houltham, S.D. and D.S. Rowlands, A snapshot of nitrogen balance in endurance-trained women. Appl Physiol Nutr Metab, 2014. 39(2): p. 219-25.

9. Butterfield, G.E., Whole-body protein utilization in humans. Med Sci Sports Exerc, 1987. 19(5 Suppl): p. S157-65.

10. Forbes, G.B., Body fat content influences the body composition response to nutrition and exercise. Annals of the New York Academy of Sciences, 2000. 904(1): p. 359-65.

11. Hall, K.D., Body fat and fat-free mass inter-relationships: Forbes's theory revisited. British Journal of Nutrition, 2007. 97(06): p. 1059-63.

12. Elia, M., R.J. Stubbs, and C.J. Henry, Differences in fat, carbohydrate, and protein metabolism between lean and obese subjects undergoing total starvation. Obes Res, 1999. 7(6): p. 597-604.

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