Discussions of veganism versus an omnivorous diet (or even Carnivore diet!!!) invoke some heated debates.  In some circles it’s almost like religion and politics, a conversation you don’t dare to bring up.  But if you care about building and maintaining muscle mass (and we submit, you should) then it’s a topic worth digging below all the emotional and philosophical noise.  

Traditionally many weight lifters, body builders, strength coaches and other players in the muscle and strength development world believe that a post workout steak or other fleshy feist is the best option for lean muscle mass gains to support strength training.    

A very recent paper, published less than 2 weeks ago helps to kick this assertion off its pedestal.    

In short, it doesn’t seem to matter what the source of your amino acids (the protein building blocks) are, as long as you get a sufficient amount.

Co-authored by McMaster researcher Stuart Phillips, this study enrolled 19 vegans and 19 omnivores who were all untrained males who weighed the same (73kg).  Participants were similar heights, similar body composition and had similar baseline levels of strength.  Pre study dietary analysis revealed similar caloric intake, however the omnivores consumed more protein (1.18g/kg per day) versus the vegans (0.91g/kg per day).  The omnivores were also consuming more Leucine per day (7g/day) versus the vegans (5g/day).  The vegans were consuming higher amounts of fiber per day (39g/day vs 19g/day).  

Each of the participants underwent a 12 week resistance training program consisting of 2 supervised training sessions a week.  Dietary protein intake was adjusted and matched for both groups at 1.6g/kg (primarily from food sources, supplemented for each where required), which is optimal for muscle protein synthesis while strength training.    

Measurements including leg lean mass, quadriceps muscle size, max leg press and extension strength were measured.  Compared to their pre-intervention measurements both groups improved in muscle mass, size and strength, but there were NO DIFFERENCES between the vegans and the omnivores on any variable.  The source of the protein thus did not seem to matter in magnitude of the gains.    

Arguments such as poor plant protein digestibility, poor stimulation of muscle protein synthesis or reduced blood amino acid levels have been made in the past to prop up the animal protein is better for gains argument.  And there are some half truths in these arguments.  But when the cards are all on the table and we test the end results of muscle development and strength gains (not some of the markers of the process) from strength training the results are negligible.

This research alone is probably not enough to tip the scales one way or another for you in terms of eating more plant based protein.  However, you may also want to consider which is better for longevity.

We have previously written about the deleterious impacts of excessive red meat and processed meat consumption.  

An increase of one serving per day of unprocessed meat consumption over a 4 year period was associated with a 20% increase in all cause mortality in the subsequent 4 years.  For processed meat, it was even worse.

Longevity researcher Valter Longo and associates have reported higher intake of animal protein is associated with higher levels of mortality.  Conversely higher intake of plant based protein is associated with lower levels of mortality.  There is some nuance (as always!) to consider in these statements.  For example the difference in mortality rates are less significant when processed meats are removed from the diet and also when no other negative lifestyle factors were present (ie. smoking, heavy drinking, overweight/obesity and physical inactivity).

It is quite likely that if animal protein quality is optimized and frequency of consumption is minimized the difference in longevity would also disappear.  Meats sourced locally, ideally direct from farm, where animals have not been subjected to hormones, steroids or antibiotics and have been raised humanely and fed high quality, organic diets are best.  Meats found in most grocery stores and restaurants do not meet these criteria.  

To circle back to the primary topic of this article: the beans, lentils, nuts, seeds and grains that pack a protein punch are just as good at delivering resistance training results as their animal sourced counterparts (and you might just live a little longer too!).