Is pea protein less effective than whey?


Short answer: Probably not.

Longer answer: Hot and fresh out the proverbial kitchen is a study in the journal Sports that compares muscle growth and performance between people supplementing with pea protein powder and people supplementing with whey. The conclusion:

…ingestion of whey and pea protein produce similar outcomes in measurements of body composition, muscle thickness, force production, WOD performance and strength following 8-weeks of HIFT.

In other words: there was not a significant difference between those chugging pea protein and those chugging whey.

Now the details: The study looked at the bodies and performance of 15 men and women before and after an 8-week high-intensity functional training (HIFT = Crossfit-style) program.

Before and after the 8 weeks of training, the scientists measured their muscle thickness (thicccccness)(via ultrasonography), bioelectrical impedance analysis (to scope out how much of their body is fat vs. water vs. lean mass), and two “benchmark WODs” (workout of the day, a term made popular by Crossfit).

The participants improved the one rep max for both their back squats and deadlifts. However,  the groups’ body composition, muscle thickness, and performance in either WOD did not improve to a statistically significant degree.

This is an interesting takeaway on its own.

Eight weeks of Crossfit and there was no significant improvement in body composition? Really? Really? Yes. This is beyond the scope of the study, but we probably know why: (1) it takes longer than eight weeks to turn bodies around to the point of statistical significance, (2) diet matters, and is not considered for this study (beyond protein shake intake), and (3) checking off a box that says you did the workout doesn’t mean you did it with any sort of fire.

But back to the real point of the article: there was no major difference between the two groups. That’s awesome to hear, but when considering the limitations of the study, it’s clear that more research needs to be done.

First of all, the sample size was very small, which makes measuring statistical significance way wonkier. Chance and outliers can have a profound effect on a sample size of 15.

Secondly, if the report did not find worthwhile changes in muscle thickness, workout performance, or body composition, how do we conclude that whey is good for building mass, and that pea protein is just as effective? We can’t. This study needed more time, more workouts, and more people in order to confidently conclude that protein shakes using either pea or whey are equally effective for adding muscle or strength. According to this study, neither were particularly effective, so it’s hard to say we learned anything valuable about supplementing and improvements in muscle thickness or strength.

How-freaking-ever, this is not the only study that looks at pea protein vs. whey. Here’s one with a sample size of 161 (all dudes, because science still thinks that women’s hormonal cycles are too wild and unfathomable to include in scientists’ very serious variable-limiting work) that saw significant improvements in strength and concludes that pea protein worked just as well as whey. From the study:

…the supplementation with pea protein promoted a greater increase of muscle thickness as compared to Placebo and especially for people starting or returning to a muscular strengthening. Since no difference was obtained between the two protein groups, vegetable pea proteins could be used as an alternative to Whey-based dietary products.

And…that’s about all I can find on the subject on Google Scholar. We need more science about my esoteric interests, please! If you are someone with a bunch of money to blow on research, consider reaching out to Dr. Anastasia Zinchenko, a powerlifter with a PhD in biochemistry who recently told Popular Science that she would run a study on vegan muscle growth if she got the funds to do so.

AND ONE LAST NOTE about vegan protein powder, and it’s important: despite lots of research, it’s unclear to me how concerned we need to be about heavy metals in these types of highly processed plant foods. Metals like arsenic, cadmium, mercury, and lead are found in our soil and sopped up by plants. While to some extent the presence of these metals is a natural part of eating plants, consuming plants in these concentrated powders may not be great for us. Consumer Reports wrote that several popular brands of vegan protein powder (Vega included) have dangerous levels of heavy metals. Yikes.

I’m going to continue to research, and will let you know what I dig up. In the meantime, I’m sticking to one protein shake or less per day. I’m probably also switching to Evolve vanilla protein powder, which appears to have less of a problem with heavy metals than, say, Vega Sport.


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