An Evidence-based Review of ‘The Game Changers’

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This fantastic guest post was written by Dietetic student Zachary Wenger. This review summarises some of the main issues related to this biased and scare-mongering film, and it’s great that it has been written by an evidence-based vegan like Zachary.

You can follow Zachary on Instagram @Planted

Whether it’s for environmental, ethical, or nutritional reasons, veganism is growing exponentially in popularity, and many professional athletes are now following this lifestyle.

We can look at Venus Williams, professional tennis player, to Kyrie Irving, professional basketball player, to Kendrick Farris, olympic weightlifter. All vegan and all at the top of their game.

The Game Changers release is drawing in a ton of debate. The film was produced by James Cameron and it promotes a vegan diet, avoiding all animal products, and the athletic benefits that go along with the dietary change.

This film has had very mixed reactions – some people love the pro-vegan messages while others feel that it is biased and full of cherry-picked their claims/research.

Some background on me before I give my thoughts on the film. I’m a college dietetics major, and have been vegan for almost 3 years, for ethical reasons. My stance on the ethics, will not and cannot overshadow the current knowledge we have on nutrition. That will be apparent as you read this post. 

Plant vs. Animal Protein

“I think one of the biggest misconceptions in sports nutrition, is that we have to have animal protein, to get big and strong and perform at a high level. That’s just clearly not true.” 

That is correct, but comes with a twist. Animal protein isn’t in any way essential to the body. If you switch to plant protein, you will not spontaneously develop kwashiorkor. The issue here with plant based protein, is protein quality. 

Protein quality is characterized by the amino acid composition and digestibility. 

On average, animal based protein is digested at a 90% or higher rate, while plant protein ranges anywhere from 55% to 80% (1).

The reason plant proteins are so much less digestible is because of the “anti-nutritional” factors like trypsin inhibitors, hemagglutinins, phytates, and more (2). The good news for vegans, is that cooking techniques like soaking, boiling, steaming, and fermentation have been shown to reduce the content of these anti-nutrients (3). It doesn’t eliminate the problem, but it helps!

Side note — while these anti-nutrients aren’t ideal for proper absorption, some have been associated with potential benefits. For example, one of the anti-nutrients, phytic acid, has been linked with potential anticancerogenic activities, lowering blood glucose and blood lipids (4).

In the film, they compare 1 cup of cooked lentils and 3 oz of beef as equivalent sources of protein. The protein digestibility corrected amino acid score (PDCAAS), is widely used as a routine scoring method for protein quality evaluation. For example, an individual would have to consume 5 times the amount of a food with a PDCAAS score of 0.20 in order to equate another food with a score of 1.00.

If we look at whole green lentils, they have a PDCAAS score of 0.63-0.67 (5).  Compare that to beef, and we see that it has a PDCAAS score of 0.92 (6). Lentils have their own sets of unique benefits, but it’s false to equate the protein quality of lentils to beef. 

What are the potential downsides of consuming less digestible protein? For one, you will have to consume more kilocalories (i.e. energy). This may be an issue for those primarily focusing on body composition. A way around this, is to consume protein powders, as they are stripped from their anti-nutritional compounds, and are as digestible as animal products.

Another issue with plant proteins, is that they also contain less essential amino acids (EAA) than animal based proteins. EAA’s cannot be produced by the body, therefore they are essential to obtain through our diet. Plants are especially low in the EAA leucine compared to animal based proteins. Leucine is well known for being a trigger for muscle protein synthesis (i.e. muscle growth) (7). While leucine is most important, compared to the other EAA’s, we need all of the amino acids to generate muscle protein synthesis.

Bottom line, we do not *need* animal based protein to build muscle. We can properly build muscle on plants, and get enough protein, but that might require more kilocalories. For an athlete that wants to limit kilocalories while keeping protein high, a vegan diet may not be the *best* choice when compared to other diets.

The film deliberately didn’t discuss any of this, which I find to be extremely dishonest. 

Plant vs. Animal Burrito Blood Lipid ‘Experiment’

This part of the movie had my blood boiling (pun intended). Cardiologist, Robert Vogel, conducted an experiment with 3 NFL players, where he gave them each a plant based burrito and a meat based burrito, then compared the blood drawn 2 hours after each meal.

As we can see from the image, the blood after consumption of the plant based meal is clear and transparent, while the meat based meal resulted in a cloudy effect. This made major headlines because according to the film, the cloudy serum we see with the meat based burrito, symbolizes endothelial dysfunction. 

This sounds scary, but how much of this is science and how much of this is fear-mongering? 

The cloudy effect seen in the blood, is called postprandial lipemia.

It is physiologically normal to see a rise in triglyceride rich lipoproteins in the blood post-consumption of dietary fat.

If we tested these athletes fasted, their serum would all look identical. Hence — why the film decided not to take fasted samples. It wouldn’t have fit their agenda. Using non-fasted triglycerides is inherently flawed due to meal-timing and fat content of the last meal. 

The film claimed they added avocado to the plant based burrito, which should show cloudy serum as well. Why didn’t it? 

For one, we don’t know how much avocado was added, because this wasn’t a published study. We can’t look at the methodology, all we can do is take the films word for it, which is not how science works. Luckily, they cited a paper that apparently replicated the results they achieved (8). That paper brought some interesting points into the equation. 

The study looked at different foods in relation to the rise in postprandial triglycerides.

Olive oil, which is vegan, had the same postprandial rise in triglycerides as cheesecake and hamburger/fries!

The researchers even found that salmon had *half* the rise in triglycerides compared to olive oil! They also found that omega-3 fatty acids, vitamin C, and vitamin E improved endothelial function. 

According to the research that The Game Changers linked, and our current knowledge on postprandial lipemia, this is not an issue with consuming plants vs animals. It is simply what we see when we draw blood from an individual that just consumed a fatty meal. 

Vegan Diets and Health Outcomes:

Lastly, and maybe most importantly, the film shares success stories of individuals that have lowered their cholesterol, blood pressure, BMI, etc — from going vegan. Which brings up the question, do you need to go fully vegan to achieve these benefits?

The film shares stories of individuals following a whole food plant based diet. This diet does not include oil or processed foods, whereas a typical vegan diet may.

A whole food plant based diet primarily works because it promotes a frequent intake of fruits, vegetables and whole grains. It promotes the intake of fiber, which can lower cholesterol, increase satiety, lower blood pressure, lower risk of certain gut diseases, lower risk of heart disease, and more (9). Consuming only whole foods completely eliminates processed junk food, which could assist one in lowering kilocalories. Plants are typically lower in kilocalories, which can aid in creating a caloric deficit, and in result, helps one lose weight. We know from current research that a healthy BMI is associated with lower all-cause mortality (10). Plants are also typically lower in saturated fat. Decreased intake of saturated fat is associated with lower LDL cholesterol (11).  

— Do you *need* to go vegan to consume more fiber? No. 

— Do you *need* to go vegan to eat more fruits/vegetables? No. 

— Do you *need* to go vegan to go create a caloric deficit? No. 

— Do you *need* to go vegan to decrease saturated fat intake? No again. 

While I do agree that we are eating too much meat, I do not think that is the primary issue. The issue is that the excess of meat, is replacing what should be plants.

The average adult’s daily fibre intake in the US alone is about 15 grams/day, which tells me that plant intake is low because all plants contain fibre (12).

In order to consume a healthy diet, would one need to restrict animal products? Definitely not. Animal products have a unique, beneficial role in the diet, that plants may not provide.

Animal products aren’t essential to the diet, but are a great source of vitamins that are harder to obtain on a vegan diet, like Vitamin D and Vitamin B12.

Animal products are also an excellent source of minerals and are easier to absorb because they are not tied to anti-nutrients. Plants contain phytates and oxalates which bind to minerals like calcium and iron, making them harder for our body to absorb (13). Animal products do not have this issue. Individuals that are poor convertors of vitamin precursors, like beta carotene, may also benefit from animal products as they are already fully formed (14).

As discussed earlier, animal protein is also superior in terms of protein quality. The list goes on and on, animal products can actually be health promoting, and this is coming from a vegan!

Quality of Evidence:

The quality of evidence in this film was extremely poor. Multiple times, the film conducted experiments on 3 people and made firm conclusions off those experiments.

Let’s compare that to what is considered high quality of evidence. We would need large randomized controlled trials (RCTs), which is considered the gold standard for determining the effectiveness of clinical trials. We also want to use statistical methods to pool the data from individual research studies and come up with conclusions, which is called a meta-analysis. Having a mechanism of action is also useful, as it would describe the biochemical link/process that produces a certain effect. Observational data is also used quite a bit, which is a statistical way of gathering data from a large population of people, and simply observing. It can’t determine causality, though it can help create hypotheses, and eventually get tested in a controlled trial. 

Do you see how that is vastly different than just simply conducting experiments on 3 individuals?

We need multiple lines of data demonstrating similar results to come up with an accurate conclusion.

There were also quite a few complaints of individuals claiming this film cherry-picked the research, and used a lot of “half-truths.” I can definitely see where those complaints were coming from. I demonstrated earlier in the blog, that the film deliberately mislead their viewers on postprandial lipemia. The film made it out that animal products uniquely cause the cloudy effect in the blood, when the research *they cited* showed otherwise.

This is a prime example on why documentaries with clear agendas, can’t be trusted at face value. 


I understand that The Game Changers’ end goal is to get people to change dietary patterns, and go vegan. I respect that, I have my emotions strung to the ethics, but I find it morally wrong to conflate ethics with the actual science.

Using fear-mongering tactics on people who are uninformed, is simply not the right way to grow veganism.

This will just continue the influx of stories from individuals ditching their vegan diet because they were mislead on the potential downfalls of the diet, which in turn negatively impacts the vegan movement. 

In terms of health, there are numerous benefits related to plant-based diets. but plant-based doesn’t mean plant-only!

There is no such thing as one perfect diet, as we are all so individual, therefore different types of plant-based diets will work for different people. A vegan diet works really well for some people, whereas a more flexitarian approach works for others.

It is vital that we are make informed choices about our diet, rather than fear-induced choices on the back of biased and sensational documentaries like The Game Changers. 


  1. Sarwar Gilani, G., Wu Xiao, C., & Cockell, K. (2012). Impact of Antinutritional Factors in Food Proteins on the Digestibility of Protein and the Bioavailability of Amino Acids and on Protein Quality. British Journal of Nutrition, 108(S2), S315-S332.
  2. Sarwar Gilani, G., Wu Xiao, C., & Cockell, K. (2012). Impact of Antinutritional Factors in Food Proteins on the Digestibility of Protein and the Bioavailability of Amino Acids and on Protein Quality. British Journal of Nutrition, 108(S2), S315-S332.
  3. Gupta, R. K., Gangoliya, S. S., & Singh, N. K. (2015). Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains. Journal of food science and technology, 52(2), 676–684.
  4. Schlemmer, U. , Frølich, W. , Prieto, R. M. and Grases, F. (2009), Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis. Mol. Nutr. Food Res., 53: S330-S375.
  5. Nosworthy, M. G., Neufeld, J., Frohlich, P., Young, G., Malcolmson, L., & House, J. D. (2017). Determination of the protein quality of cooked Canadian pulses. Food science & nutrition, 5(4), 896–903.
  6. Gertjan Schaafsma, The Protein Digestibility–Corrected Amino Acid Score, The Journal of Nutrition, Volume 130, Issue 7, July 2000.
  7. Witard, O. C., Wardle, S. L., Macnaughton, L. S., Hodgson, A. B., & Tipton, K. D. (2016). Protein Considerations for Optimising Skeletal Muscle Mass in Healthy Young and Older Adults. Nutrients, 8(4), 181. 
  8. Vogel R. A. (1999). Brachial artery ultrasound: a noninvasive tool in the assessment of triglyceride-rich lipoproteins. Clinical cardiology, 22(6 Suppl), II34–II39. 
  9. James W Anderson, Pat Baird, Richard H Davis, Stefanie Ferreri, Mary Knudtson, Ashraf Koraym, Valerie Waters, Christine L Williams, Health benefits of dietary fiber, Nutrition Reviews, Volume 67, Issue 4, 1 April 2009, Pages 188–205
  10. Global BMI Mortality Collaboration, Di Angelantonio, E., Bhupathiraju, S., Wormser, D., Gao, P., Kaptoge, S., … Hu, F. B. (2016). Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents. Lancet (London, England), 388(10046), 776–786. 
  11. Sacks FM, Lichtenstein AH, Wu JHY, Appel LJ, Creager MA, Kris-Etherton PM, Miller M, Rimm EB, Rudel LL, Robinson JG, Stone NJ, Van Horn LV; American Heart Association. Dietary fats and cardiovascular disease: a presidential advisory from the American Heart Association. Circulation. 2017; 136:e1–e23.
  12. James W Anderson, Pat Baird, Richard H Davis, Stefanie Ferreri, Mary Knudtson, Ashraf Koraym, Valerie Waters, Christine L Williams, Health benefits of dietary fiber, Nutrition Reviews, Volume 67, Issue 4, 1 April 2009, Pages 188–205
  13. Angela Sotelo, Liliana González-Osnaya, Argelia Sánchez-Chinchillas & Alberto Trejo (2010) Role of oxate, phytate, tannins and cooking on iron bioavailability from foods commonly consumed in Mexico, International Journal of Food Sciences and Nutrition, 61:1, 29-39
  14. Yabuta, S., Urata, M., Wai Kun, R. Y., Masaki, M., & Shidoji, Y. (2016). Common SNP rs6564851 in the BCO1 Gene Affects the Circulating Levels of β-Carotene and the Daily Intake of Carotenoids in Healthy Japanese Women. PloS one, 11(12), e0168857. 


Maeve has been consulting on The Food Medic Educational Hub for 12 months now and has been a huge asset to the team. Her ability to translate some very nuanced topics in nutrition into easy-to-follow, informative articles and infographics is really admirable.

Dr Hazel Wallace

Founder of The Food Medic

Maeve is incredibly talented at sharing scientific information in an easy to understand way. The content she shares with us is always really interesting, clear, and of very high quality. She’s one of our favourite writers to work with!

Aisling Moran

Senior UX Writer at Thriva Health

Maeve has written extensively for NHD magazine over the last few years, producing a wealth of dietetic and nutritional articles. Always evidence based and factual, Maeve creates material that is relevant and very readable. She provides high quality work with a professional and friendly approach. Maeve is a beacon of high quality knowledge and work within the nutrition writing community; and someone NHD magazine is proud to work with.

Emma Coates

Editor of Network Health Digest

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