The benefits of pea protein for athletes: the evidence base

Pea protein is often advertised as «plant-based whey». But what exactly does scientific research show — and to what extent can its results be transferred to real athletes? Our editorial team examined the key clinical works, reviews and methodological limitations to assess where the evidence base is solid and where it is only forming.

What question researchers pose

When it comes to the benefit of a protein supplement for athletes, researchers are usually interested in a few specific outcomes: muscle mass gain, changes in strength, recovery rate and body composition. For pea protein, the main question is formulated as follows: can it provide the same adaptations to training as the «gold standard» — whey protein?

Interest in this question has a theoretical basis. Plant proteins on average contain less leucine and essential amino acids than animal ones, and in acute studies often provide less stimulation of muscle protein synthesis at the same dose. Pea protein is one of the best among plant proteins in terms of amino acid composition, so it was logical to test it in practice.

It is important to distinguish two types of studies. Acute (short-term) ones measure muscle protein synthesis over a few hours after intake. Chronic (long-term) ones track how muscles and strength change over weeks or months of training. For an athlete, the chronic results are more important, although the acute ones help to understand the mechanisms.

It is also important what pea protein is compared with: placebo, whey or other plant proteins. This determines what exactly can be asserted based on the results.

Key clinical studies

The most cited is the randomized double-blind study by Babault et al. (2015), published in the Journal of the International Society of Sports Nutrition. It involved 161 young men who performed upper-body resistance training for 12 weeks. Participants received 25 g of pea protein, whey protein or placebo twice a day.

The results showed that the thickness of the biceps brachii increased in all groups, but in the pea protein group the gain was statistically greater than in the placebo group. Between pea and whey protein no statistically significant difference was found. Strength increased in all groups with no differences between them. The authors noted that the effect was more noticeable in less trained participants.

The second frequently cited study is the pilot work by Banaszek et al. (2019). Participants engaged in high-intensity functional training for 8 weeks and received either whey or pea protein. Both groups improved indicators of body composition, strength and performance, and no substantial differences between the groups were recorded. However, the sample was small, which the authors themselves acknowledged.

These two works are often used as the main argument in favor of pea protein. They do indeed indicate that with a sufficient dose and regular training, pea protein provides adaptations comparable to whey. But, as we will show below, they should not be relied on as definitive proof.

What reviews and meta-analyses say

There are so far few specialized meta-analyses devoted solely to pea protein, so one has to look at the broader context — plant proteins in general and protein supplements as a category.

The meta-analysis by Morton et al. (2018) in the British Journal of Sports Medicine combined 49 randomized studies and showed that protein supplements during resistance training increase gains in lean mass and strength. The benefit stopped increasing at approximately 1.6 g of protein per kilogram of body weight per day. The protein source in this analysis did not turn out to be a determining factor.

The reviews by van Vliet et al. (2015) and Pinckaers et al. (2021) examined in detail the anabolic response to plant proteins. The authors concluded that the lesser anabolic effect of many plant proteins is associated with lower digestibility, a lower leucine content and a deficiency of certain essential amino acids. At the same time, these shortcomings can be compensated for by a larger dose, blends of different plant proteins or enrichment with leucine.

A study by Hevia-Larraín et al. (2021) showed that in previously untrained young people — vegans and omnivores — a high-protein plant-based diet (with a soy protein supplement) and a mixed diet with the same amount of protein produced comparable gains in muscle mass and strength over 12 weeks. Although it used soy rather than pea protein, the result supports the general idea: with sufficient protein, plant-based nutrition does not hinder adaptations.

Limitations of the evidence base

Despite the encouraging results, the evidence base for pea protein has substantial limitations, which it is honest to state.

• A small number of studies.There are few long-term randomized trials specifically with pea protein.
• Small samples.Some works are pilots, with a small number of participants, which reduces statistical power.
• Untrained participants.Results in beginners do not always transfer to experienced athletes.
• Funding by manufacturers.Some studies are supported by companies that produce pea protein; this does not make them unreliable, but requires independent replications.
• Narrow populations.There is little data on women, older people and endurance athletes.

A separate methodological problem is that the absence of a statistically significant difference does not prove equivalence. To assert that pea protein is «the same as whey», special equivalence studies with a sufficient number of participants are needed.

Also, in many studies the total protein intake of participants was quite high. In such a context, differences between protein sources are naturally smoothed out. In people with low total protein intake, the quality of a specific source may matter more.

Finally, data from acute studies indicate that at the same small dose plant proteins often give a lesser anabolic response. For older people, in whom the sensitivity of muscles to protein is reduced, this may be practically important.

Practical conclusions for athletes

What follows from all this in practice? First, pea protein is a working tool for people who train and want to increase protein intake without products of animal origin or without lactose.

Second, if you choose pea protein, it is reasonable to use slightly larger portions than for whey, or to combine it with other plant proteins, for example rice. This compensates for the lower content of leucine and methionine.

Third, the overall context is more important than the specific supplement. The ISSN position (Jäger et al., 2017) recommends 1.4–2.0 g of protein per kilogram of body weight per day for physically active people. If this amount is achieved, the choice between pea and whey protein becomes secondary.

Fourth, athletes who undergo doping control should choose products with independent certification, since the risk of contamination exists for any supplements, including plant-based ones.

Editorial conclusions

The evidence base for pea protein is small but consistent: with a sufficient dose and regular training it promotes gains in muscle mass and strength, and in the available studies it was not statistically inferior to whey.

At the same time, these conclusions are based on a limited number of works, mostly with untrained young men, so it is premature to speak of full equivalence with whey.

For practice, the most important things are the total amount of protein, the regularity of training and, if needed, the combination of plant sources.

We also recommend reading our articles «Pea protein: what it is and how it works», «How to take pea protein: dosage, timing, duration» and «Myths about egg protein».

References

1. Babault N, Païzis C, Deley G, et al. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, placebo-controlled clinical trial vs. whey protein. J Int Soc Sports Nutr. 2015;12(1):3.
2. Banaszek A, Townsend JR, Bender D, et al. The effects of whey vs. pea protein on physical adaptations following 8-weeks of high-intensity functional training (HIFT): a pilot study. Sports (Basel). 2019;7(1):12.
3. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384.
4. van Vliet S, Burd NA, van Loon LJC. The skeletal muscle anabolic response to plant- versus animal-based protein consumption. J Nutr. 2015;145(9):1981–1991.
5. Pinckaers PJM, Trommelen J, Snijders T, van Loon LJC. The anabolic response to plant-based protein ingestion. Sports Med. 2021;51(Suppl 1):59–74.
6. Hevia-Larraín V, Gualano B, Longobardi I, et al. High-protein plant-based diet versus a protein-matched omnivorous diet to support resistance training adaptations: a comparison between habitual vegans and omnivores. Sports Med. 2021;51(6):1317–1330.
7. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.