Going ‘all in’ on plant foods is a trend that is showing no signs of slowing down. But for those who are all about the muscle gainz for their sport and health, should you be concerned that your hard-won muscle growth is being compromised because you’ve embraced a mostly plant-based life? In this podcast, I’ll delve into the key differences between animal and plant-based proteins, the main supplements on the market for each, and profile the latest research on how people fare for muscle growth when weight training on a vegetarian versus an omnivore diet.
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Episode transcript
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Going ‘all in’ on plant foods is a trend that is showing no signs of slowing down. But for those who are all about the muscle gainz for their sport and health, should you be concerned that your hard-won muscle growth is being compromised because you’ve embraced a mostly plant-based life? In this podcast, I’ll delve into the key differences between animal and plant-based proteins, the main supplements on the market for each, and profile the latest research on how people fare for muscle growth when weight training on a vegetarian versus an omnivore diet.
Links referred to in the podcast
Episode transcript
To access the full episode transcript, go to the following link and select the individual podcast episode and then click on the ‘Transcript’ tab https://thinkingnutrition.buzzsprout.com
Connect with me
Instagram: doctimcrowe
Facebook: Thinking Nutrition
Twitter: CroweTim
Going ‘all in’ on plant foods is a trend that is showing no signs of slowing down. But for those who are all about the muscle gainz for their sport and health, should you be concerned that your hard-won muscle growth is being compromised because you’ve embraced a mostly plant-based life? In this podcast, I’ll delve into the key differences between animal and plant-based proteins, the main supplements on the market for each, and profile the latest research on how people fare for muscle growth when weight training on a vegetarian versus an omnivore diet.
Protein is important. Pretty sure you all understand that. It is made up of amino acid building blocks that the body can resynthesise into a whole host of functional and structural proteins. Some of those amino acids are essential in that our body either can’t make them, or can’t make them in sufficient quantities. Hence the focus on biologically complete protein which most animal-based protein foods supply.
Now that doesn’t mean that plant-based proteins are inferior as even though some sources are low in some of the essential amino acids, combining a variety of different sources easily compensates for this. Rice and beans is an example of a ‘protein complete’ meal because one protein source makes up for a deficiency in the other of certain amino acids. And then there are some plant proteins like soy and quinoa which are considered complete protein sources. So really, it would be dark-ages thinking indeed for someone to think that a vegetarian diet is somehow nutritionally inferior from a protein standpoint.
Outside of a whole diet, protein supplements dominate the market for sportspeople to help meet higher protein needs. Now I won’t go into too much detail on if these supplements are really needed or not, as I did a whole podcast on protein supplements back in episode 8 which you can check out, so a quick refresher for today.
The main type of animal-based protein supplement on the market is dairy based. The two main proteins in dairy are casein and whey. They are digested and absorbed at different rates, with whey appearing more quickly in the bloodstream than casein. Most protein supplements are based on whey, but that’s more due to convenience because of its ready availability: it’s a waste product from cheese manufacturing after all.
Whey protein is of particular interest because it appears to have a stronger anabolic effect on muscle growth, thanks to a higher content of a specific essential amino acid called leucine. Leucine is a branched-chain amino acid and is particularly popular for its ability to build muscles and activate a protein known as mTOR, which triggers muscle protein synthesis.
The whey protein supplement market falls under three main types of protein. First, there is whey protein concentrate which is typically 70-80% protein by weight with small amounts of lactose and fat. It’s one of the cheaper forms of whey. Then next we have whey protein isolate or WPI. WPI powder is usually 90% protein by weight, with negligible amounts of carbohydrates and fat. Because of its higher protein content, it costs more than whey protein concentrate. And finally, there is whey protein hydrolysate which is characterised by shorter peptides or amino acid chains, supposedly resulting in even more rapid digestion but evidence to date is conflicting.
With a growing interest in following a vegetarian way of eating, soy protein is also a popular option. Soy is considered a high biological value rapidly digested protein. It comes as both a soy concentrate and soy isolate. It is often used in mixed protein supplements and protein bars. While the balance of research indicates that whey protein may have a small edge for muscle building, some studies have found soy foods to be just as effective as whey protein in terms of its ability to promote gains in lean muscle mass.
Pea protein powder is another protein powder that is growing in popularity especially among vegetarians, vegans and people with allergies or sensitivities to dairy or eggs. Pea protein is not absorbed as fast as whey protein but is absorbed quicker than casein protein. There hasn’t been a lot of research into the muscle-building properties of pea protein, but at least one 12-week study involving 161 men doing resistance training who took either 50 grams of pea protein, whey protein or a placebo non-protein powder each day saw similar increases in muscle thickness between the pea and the whey protein and both were superior to placebo so there could be something to the pea protein story here.
Even studies that use lower-quality protein such as that derived from wheat can elicit a significant muscle protein synthesis response if greater amounts of it are consumed and this may be an effective strategy to compensate for its lower protein quality. So, the story here is that adequate protein overall in the diet may trump the source of protein so long as the diet is varied.
Vegetarian
So, onto the crux of today’s podcast of how high-protein plant-based diets may fare against a similar high-protein diet that is omnivore based. Before I jump into drilling down into a recent intervention trial that has just been done addressing this question, I’ll look at what the observational evidence may say. Certainly, the world of elite sport is replete with athletes who are following vegetarian or vegan diets (sorry, but I’m not going to use the meaningless buzzword of ‘plant-based’ as it tells you little about how much of a person’s diet may be based on plants!).
Clearly, it is possible to excel at the highest level of sport without needing to eat animal-based foods if that is an important health, environmental, religious or ethical issue for you. To support this, from an observational study published in 2016, the diets and physical attributes of 27 vegetarian and 43 omnivore competitive endurance athletes were looked at. Each person in the vegetarian group had followed the diet for at least two years and there was a mixture of vegan and lacto-ovo vegetarians amongst the group. There was little difference in protein intake according to body weight between vegetarians and omnivores. Although vegetarians ate more carbohydrates and fibre, they did have less vitamin B12 which is not surprising at all. One interesting finding was that vegetarians had more iron in their diet than omnivores. But because plant-based iron is less bioavailable than animal-based iron then this may bring the vegetarians back on par with omnivores. And I’ll link to the study in the show notes. https://pubmed.ncbi.nlm.nih.gov/27854281
The key finding from the study though was in terms of sports performance differences between the two groups. For the males, there was little difference in cardio-respiratory fitness or strength between the vegetarian and omnivores. The surprising finding though was in women. Women following a vegetarian diet had 13 percent greater VO2max scores than women eating an omnivore diet.
So all fairly positive so far for those that choose to follow a vegetarian diet. And now onto the new research published in only June of this year that wanted to see how when you control for how much protein is eaten, if you can you see a difference in muscle growth between people following a vegetarian diet and those following an omnivore diet. I’ll link to this study in the show notes https://pubmed.ncbi.nlm.nih.gov/33599941
Now straight out, this was not a randomised controlled design study. Instead, 38 healthy young men who were already following a vegan or omnivore diet for at least one year and were untrained were recruited into the study so there is some inherent bias here already for differences that may exist between people who choose to follow such diets. But there was a controlled intervention and, in this case, it was a matched 12-week supervised resistance training program that was lower-body focussed as well as dietary monitoring and intervention to keep protein intake at a level of 1.6 grams per kilogram of body weight for everyone. Protein supplements (either soy or whey where appropriate) were used to help ‘top up’ protein when needed. Of interest though, for those following a vegetarian diet, they needed to supplement a lot more with soy protein to get to the protein goal.
The big question: what happened? As expected, both groups enjoyed the muscle gainz considering these were mostly untrained volunteers. There was a significant increase in lean muscle mass across a whole bunch of different body sites by pretty much identical amounts between the two groups with any differences not significant as in some cases the vegetarians gained slightly more muscle mass at one certain site, while in other cases the omnivores had higher amounts – all of this was just random biologic variation.
This was a relatively small study so it may not have been large enough to pick up significant differences, but if they were there, they would have been small differences of likely not meaningful benefit. And the study focus was mostly on lower-body strength so it’s unclear if it can be applied to whole-body protein gains, but I can see little reason why it should not.
But the results do broadly agree with the greater literature field here that animal-based protein in the context of a varied and protein sufficient diet has little advantage when it comes to muscle growth when comparing it to a plant-based protein diet that is varied.
Most sources of protein will do the job if you’re focussing on muscle and strength gains with the two most important factors being getting sufficient protein containing a mix of different protein types which is especially important for a vegetarian diet to get all of those essential amino acids so here, a protein supplement may be more important. The second factor is probably even more important: some hard work in the gym.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.