Dietary Protein & Sport: Why non-animal proteins have a role to play

Written by Dr Alistair Monteyne

Dietary protein is vital for facilitating recovery and adaptation following exercise. In this blog post, we will explore why dietary protein is particularly important for athletic populations and how to optimise dietary protein intake for athletic endeavours. Moreover, we will highlight the role that non-animal proteins, including mycoprotein, can play in meeting these protein goals.

What is protein and why do we need dietary protein?

Proteins are molecules of varying size and complexity made up of amino acid ‘building blocks’. They perform a bewildering array of functions within the human body, including providing our tissues with structure and regulating metabolism. The proteins inherent within a tissue determine its function, with specific proteins in muscle tissue conferring the ability to contract and facilitate movement.

Proteins are constantly being synthesised and broken down (‘turning over’) at varying rates in all tissues, with some amino acids then lost from the body through excretion. These amino acids, therefore, need to be replaced by protein from our diet. Following ingestion, dietary proteins are digested and broken down into amino acids.

They are then absorbed in the small intestine and released into circulation, where they can be taken up by tissues, stimulating the synthesis of new proteins. Muscle tissue represents ~50-75% of all body protein and is inextricably linked to athletic performance.

As such, from an athletic perspective, we are largely concerned with the synthesis of new muscle proteins - muscle protein synthesis (MPS). This is a process that we can measure in a laboratory environment, allowing us to characterise how well different protein sources support this process.

Why is protein important to athletes?

Exercise increases the rate of MPS and to a lesser extent the rate at which muscle proteins are broken down, which persists for up to 48 h¹. This occurs due to the need to repair damaged proteins, but also to ‘remodel’ proteins in response to the stimulus that exercise provides. If this remodelling process is repeated over time (i.e. exercise training) we increase the quantity of specific muscle proteins, rendering us better adapted for that exercise modality.

This is one reason we get fitter if we persist at an activity over time. The greater turnover of protein induced by exercise means that athletes have increased dietary protein requirements, and without adequate dietary protein will be unable to optimise the process of repair and adaptation.

Typically, we tend to think of dietary protein in the context of strength training, but the same is true for endurance athletes who similarly need to repair and remodel specific proteins, whilst also replacing amino acids that have been utilised for fuel during exercise ^2,3.

Protein for muscle recovery – how much is needed?

Whilst this remains a nuanced topic, the following recommendations serve as a general guide.

A serving of 0.3-0.4 g of protein per kg of body mass (24-32 g for an 80 kg individual) per meal, or snack, provides adequate protein to transiently stimulate muscle protein synthesis rates after exercise.
A daily protein consumption of around 1.8 g per kg of body mass optimises recovery and adaptation across the vast majority of the athletic spectrum, from endurance athletes to strength athletes ^4,5. Requirements might be slightly higher, ~2 g per kg body mass or above, if an athlete is in a periodised weight loss phase ⁶.
The evidence for the wisdom of distributing protein across the day is inconclusive, but spreading protein relatively evenly across the day (every ~3-4 h) is logical and may confer small benefits to an athlete ⁷. There is nothing inherently advantageous about consuming protein immediately after exercise ^8,9, but it may confer small benefits in maximising recovery. Consuming a serving of protein before sleep is also an effective strategy to aid in meeting protein goals, and maximising recovery ^10,11.

Does protein source matter and how to get protein without meat

Much of the research investigating post-exercise protein has focused on animal-derived proteins, particularly dairy. Early studies found animal-derived proteins to be superior to plant-based proteins in their ability to stimulate MPS, albeit compared to only a limited number of plant-based sources (i.e. soy protein) ^12,13.

This developed a narrative that non-animal derived proteins were inferior concerning their ability to support recovery and adaptation. However, more recent evidence has challenged this view, and we are now observing that some non-animal-derived proteins can be just as effective at stimulating MPS and supporting adaptation.

We performed a series of studies to investigate whether mycoprotein, the fungal-derived protein that is the main ingredient in Quorn products, could support post-exercise recovery and adaptation.

Mycoprotein has a high protein content (45% dw), a balanced profile of essential amino acids, and is properly digested and absorbed¹⁴. Initially, we compared mycoprotein to a similar serving of milk protein (a ‘gold standard’), demonstrating that the ingestion of mycoprotein stimulates resting and post-exercise MPS to a slightly greater extent than the milk protein¹⁵.

Several studies from our laboratory have since confirmed the observation that mycoprotein strongly stimulates MPS^16-18. Furthermore, evidence is accumulating that other non-animal derived proteins can also robustly stimulate both resting MPS (algae¹⁸, wheat¹⁹, pea²⁰, corn²¹, potato²², plant-blends²³), and post-exercise MPS (algae ¹⁸, potato²², pea¹⁷, protein-blend ^17,24). The evidence is now clear that ingesting around 30 g of high-quality non-animal-derived protein can stimulate high rates of MPS.

Protein and muscle recovery when consuming mycoprotein

With our work on mycoprotein, we then wanted to look beyond a single meal, so we switched tack to investigate MPS rates over several days, allowing us to look at the effect of a whole diet. We compared a high protein omnivorous diet to a mycoprotein-rich vegan diet, alongside daily resistance exercise. We observed that the omnivorous and mycoprotein-rich vegan diets supported equivalent daily MPS, in both young and older adults^25,26.

This was an important finding, as it provided underpinning evidence that non-animal-derived diets could support recovery and adaptation over multiple days. We translated this still further by examining whether a non-animal-derived diet could optimally support changes in muscle size and strength.

To do so we put people on a resistance training program for 10 weeks, consuming either a high-protein omnivorous diet or a mycoprotein-rich vegan diet. We observed that both diets supported training adaptation to an equivalent extent, demonstrating almost identical increases in muscle size and strength²⁵. Consequently, we have now demonstrated that mycoprotein can support recovery and adaptation to exercise from a molecular level to the level of movement.

Whilst more work is undoubtedly required across a range of different sports and dietary permutations, we have good reason to now believe that high-quality non-animal-derived protein sources can facilitate post-exercise recovery and adaptation to training similarly well to animal-derived proteins. It then comes down to a question of preference, rather than necessity.

Summary

Dietary protein is essential to optimise recovery and adaptation following exercise, and is a cornerstone of sports nutrition. Athletes, and recreational exercisers, require slightly greater protein intakes to support their training, and this protein can come from both high-quality animal and non-animal sources. Our work shows that mycoprotein can serve as a high-quality protein within the diet, demonstrably supporting post-exercise recovery and adaptation to training.

About the author

Dr Monteyne graduated from Loughborough University in Sport & Exercise Science in 2015, before completing an MSc in Sport & Exercise Nutrition at the same institution. Following this, Alistair took a PhD position in the Nutritional Physiology Research Group (NPG) at the University of Exeter, under the supervision of Professor Benjamin Wall and Professor Francis Stephens. Alistair was awarded his PhD in 2021 for the thesis entitled “Mycoprotein & Skeletal Muscle Anabolism”, which characterised the effect that the alternative protein mycoprotein has on muscle protein synthesis rates and muscle mass, in both young and older individuals. Following his PhD, Alistair undertook post-doctoral training within the NPG, before joining the Department of Public Health and Sport Sciences at the University of Exeter in 2023 as a Lecturer in Nutritional Physiology.

References
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