In Part One, I discussed my general thoughts and criticisms about the film. I recommend reading it first, but you do you boo.

Claim #1: Gladiators Were “Plant-Based”

This is where the film kicks off; Wilks discovers a piece of research that discovered that gladiators were plant-based. Trying to read the original study [1] was a bit of a challenge for me (I am not an expert by any stretch when it comes to stable isotopes, and call me cynical but I doubt Wilks is either). Anyway, the researchers of this study looked at gladiator bones found at a burial site in Ephesus; the only known gladiator graveyard in the world. By looking at the levels of calcium, nitrogen, sulphur and trace elements, they are able to make assumptions about their dietary patterns. But the main aspect focused on in the film is a compound known as strontium. The strontium level is tested by burning the bone sample – if the flame turns blue, strontium levels are low (indicative apparently of a carnivorous diet), if they are high (indicative of vegetarian diet), it turns red. Low and behold, in the film – the flame burns red.

While the paper concludes that this particular subset of gladiators ate a primarily plant-based diet, this was also reflective of the dietary patterns of the entire region. As would be expected 1800 years ago – people ate what was locally available.

Wilks also dubs gladiators “highly prized […] professional fighters [who] got the most advanced training“. While this is the image most of us have (shoutout to 2000 Russel Crowe), it’s not quite reality. Most gladiators were slaves: ” The social group of gladiators mainly consisted of prisoners of war, slaves, and condemned offenders […] Contestants with swords (ad gladium) had to fight in the arena without prior special training, which in most cases meant certain death” [1]. The culture of gladiator fights was brutal – the people wanted a show, and the more blood, guts, and death, the better. So, “professional/highly prized” is a stretch. In terms of keeping them alive in between fights, it is likely they were fed whatever was cheap and easily available.

The study itself has come under criticism, acknowledged by the authors themselves, including over the inaccuracy of strontium as a testing method and the fact that elements in the bones change over time, impacting accuracy.

Studies examining gladiator bones from other sites found higher levels of nitrogen suggesting that, like all populations at the time, diets varied depending on geographical location [2]. Two of the gladiators from the Ephesus study had significantly different isotope levels to the rest, suggesting they were immigrants from other locations. In particular, they had higher levels of sulphur, which is indicative of a diet high in seafood.

It’s also important to note that a diet “predominantly vegetarian”, does not mean vegan, and to be clear the study does not conclude that animal foods were completely absent from the gladiator diet. In all fairness, the film never claims they were 100% vegan, but it conveniently skips over any potential evidence of meat or seafood in the gladiator diet.

Whatsmore, Karl Grosschmidt, one of the researchers of the Ephesus study has said:

Unsurprisingly, this was omitted from the documentary. I don’t really think “go plant-based to get chubs” really fitted the image they were trying to portray.

Claim #2: Protein As Energy

The film starts discussing the idea that people wrongly believe that protein is fuel for exercise. Forgive me if I’m wrong, and I’m sure there are people out there who believe this, but I wouldn’t say it’s a commonly held belief. Protein is used by athletes (and gym-buffs) primarily to build and maintain muscle, while carbohydrates are targetted for energy. Wilks traces this back to the 1800s, when a scientist known as Liebig concluded that muscular exertion required protein, rather than carbohydrate or fat. As the documentary points out, although this was later found to be false, Liebig was capitalizing from his “discovery” by selling beef extract products, and the belief that protein was fuel for exercise persisted. While this is all true, whether it persisted the full 200 years since, is another question entirely. Anyway, Wilks argues so, so I’ll give it the benefit of the doubt.

This portion of the documentary focuses on Scott Jurek, an incredible endurance runner. What Jurek has achieved in his career is nothing short of phenomenal (2 marathons a day, every day, for 46 days – like what?!). He also happens to be vegan.

Wilks discloses that he was “confused about how [Jurek’s] meat-free diet could possibly give him enough energy“. Yes, I suppose we are used to seeing marathon runners gorging on steaks mid-run. This is followed by an excerpt from Dr James Loomis (former team physician for St. Louis Rams) who explains his athletes used to load up on animal protein at pre-game dinners because they felt it would give them energy. He then explains that, in actual fact, this is an outdated idea and energy for exercise actually comes from carbohydrates. While I agree that the fitness industry is overly fixated on protein, in my mind, this has more to do with muscle building than energy. While it’s possible I’m a little disconnected from the average level of nutritional knowledge, I just cannot imagine it would come as a surprise for people (particularly those with a career in sport & performance) that marathon runners and high-performance athletes get energy from carbs. But maybe I’m wrong.

Claim #3: Protein Depletes Muscle Glycogen

Dr Loomis then proceeds to explain that sacrificing carbohydrate calories for protein calories means developing “chronic glycogen depletion” – leading to fatigue and impaired performance. While there is a certain element of truth in what he says, it’s not fully accurate. Do you already see a theme emerging?

So going back to the film’s claims, yes – carbohydrate consumption after exercise helps us replenish glycogen stores [6]. However, to say that replacing carbohydrates with protein leads to glycogen depletion is a stretch. In very low carbohydrate diets (e.g. <20% of total calories), we do see some difficulty replenishing glycogen stores in the initial stages of the diet (between a 30-50% reduction), however, studies show that the body adapts after ~6 weeks of the diet. Once adaptation has taken place, even if glycogen stores remain reduced, this has not shown to limit performance – however, it may not be ideal for all athletes [7][8][9].

Now, I’m not advocating a ketogenic diet here. But it shows why the language used in the documentary is beyond misleading. Studies have shown time and time again that regular training and a diet rich in carbohydrates is indeed the best way to restore glycogen stores compared with a low-carb diet. But as for protein – let’s not knock it either. Protein consumption post-exercise (0.3-0.4g/kg body weight), particularly when carbohydrate intake isn’t adequate, augments glycogen synthesis [10][11].

So “chronic depletion” my Great Aunt Margorie.

Claim #4: – Sourcing Our Protein

The film displays a pretty, but rather useless, graphic to show that vegans get protein in excess of 70% than requirements, while meat-eaters get half of their protein from plants. Okay, so maybe useless is a bit harsh – I do actually think it answers the common “omg how do you get your protein?” rhetoric vegans get bombarded with. And I’ll pretend it wasn’t intentionally designed to misleadingly make it seem like plant-eaters get more protein than meat-eaters (see below).

But to clarify, these requirements are to avoid protein deficiency, which is extremely uncommon (aside from in developing countries, where people are generally just starving). Optimal protein intake is a good bit higher (

Note – protein recommendations to avoid deficiency are 0.8g/kg per day. Optimal protein intake, particularly for athletes, is 1.2-1.4g/kg per day [12]).

But then here comes literally the one part of the documentary that never fails to literally drop my head in my hands with disbelief – James Wilks is “surprised to learn that all protein originates from plants”. WHAT DOES HE THINK ANIMALS EAT?! (*insert mental image of a jacked cow chugging back a protein shake*). I don’t know, I am triggered, what can I say. If James Wilks really didn’t know the basics of the animal food chain, why are we watching a nutrition documentary narrated by him?

Claim #4a: Peanut Butter Sandwich vs Steak

This section has been hammered with criticisms, but I actually think it’s valid enough. The film states that 3oz of beef or three large eggs have a similar amount of protein as a PB sandwich or 1 cup of cooked lentils.

People took issue with the fact that the calories of a PB sandwich were significantly higher than the rest. However, remember that beef, eggs, or indeed lentils, are often implemented to meals (albeit larger & probably more filling), which by then would likely have similar calorie content to the sandwich.

So, eating peanut butter sandwiches all day isn’t likely optimal, but I think it proves the point that even basic, everyday plant-based meals do contain good amounts of protein.

Claim #4b: Go Straight to the Source – Plant Vs Animal Protein

So back to what I said about the protein-chugging cow.

Wilks frames it as “cows, pigs and chicken are just the middlemen” – i.e. why eat them when we can go right to the source (plants)?

Now, I know I’m repeating myself but I just want to clarify – I do not believe that we need to get protein from animals. But, I think that education is vital to achieving a healthy vegan diet. To say that achieving an optimal protein intake as a vegan is easy is misleading. From personal experience – it’s not. Is it possible? 100%. But it’s challenging, and if we don’t educate people about the fact that it takes a bit more planning and effort to do so, then we’re doing them an injustice.

The film kind of spins the idea that plant protein is superior to animal protein. This is not true, but what I also cannot say is that animal protein is superior to plant protein either. They’re different – that’s it. We really need to stop pitting certain ways of eating against each other as if there is one right way of eating. Let’s give the design of the human body and the world around us a little more credit. What matters is that we understand what is in our food and how to eat, in the context of the whole diet, to best achieve health.

HOWEVER…

There are concerns to be had when a diet is overly reliant on animal-sourced protein. Protein is not generally eaten in isolation – it comes part and parcel as part of a “food matrix”. Increasing consumption of animal proteins will usually mean increasing consumption of saturated fat, which, when eaten in excess can be problematic for health. In comparison, a diet rich in whole plant-based proteins will mean a diet rich in fibre (which has a whole host of benefits), antioxidants, phytochemicals vitamins and minerals.

Hence, why neither plant nor animal protein can be considered superior. Statements doing so are overly simplistic. Plant-based proteins are of lower quality than animal proteins but come with an arguably more beneficial nutrient profile, while the limitations in protein quality can be overcome using the correct strategies, such as consuming complementary proteins. This heavily relies on getting a wide variety of plant proteins, which requires more planning and preparation. So vegans can achieve optimal protein intakes for athletic performance and/or muscle building, as long as these aspects are taken into consideration.

Claim #5: Strongman footage

Like with the other athletes, Patrick Baboumian is incredible. As a vegan, he gained 25lbs; although it doesn’t mention that this may or may not be down to steroids (fairly common in strongmen), or at the very least, the four protein shakes he drinks a day to reach his 410g protein target. But hey ho – it’s possible to be jacked and vegan – no arguments there. (Note: most athletes, particularly power-lifters/body-builders drink protein shakes so I don’t think it’s particularly significant that Patrick does the same).

My issue here though is that they kind of insinuate that the success of any vegan athlete is down to their choice to not eat meat. I love that these amazing athletes are showing what can be achieved, but the film does conveniently try to put the emphasis on the diet. For example, the film shows Patrick breaking a world record by carrying 1223lbs, but fail to mention it was that this has since been beaten by over 300lbs by athletes who eat meat. Similarly, when McGregor lost a fight to Diaz, a vegan, they really made sure to emphasise McGregors meat consumption. But when Jennings (vegan) lost to Klitschko (meat-eater), it’s glossed over. Obviously, I don’t think one athlete will win over another because they eat meat. But that’s my point – these athletes are incredible, and their dietary patterns play a huge role, but it’s not because of the inclusion or exclusion of animal products.

Jennings actually puts it quite well:

I completely agree, so again this is really a battle of high quality vs poor quality diets – not whether you are vegan or not. As I have already touched on, many of the athletes quite openly share that they previously ate a lot of fast-food, such as fried chicken, and very little vegetables.

Claim #6: Battle Rope Session

“One hour” and not even a sign of heavy breathing. Pay attention to the background and you’ll see everyone in the gym is also doing the same activity the whole way through the footage. While it’s possible not the entire “hour” was filmed, kinda sus if you ask me. But anyway – yes, yes – very believable. Moving on.

Claim #7: Beetroot Juice & Bench Press

So you wanna “beet” your bench press, do ya? (pun 100% intended – I’m sorry I couldn’t resist, I genuinely tried).

The film claims that beetroot juice can allow you to bench press “19% more total weight”. This is a perfect example of why language matters; and here, they’re using misleading language to imply something that isn’t true, while technically avoiding straight-up lying. Say you currently bench press 110kg. The implication the film makes is that I take a drink of squeezed beetroot and BOOM – 130kg. Sound too good to be true?

What the study actually did was have two groups complete 3 sets to failure with 60% of the one-rep max. One group was supplemented with beetroot juice, and the other with a placebo. They found that the group who had the beetroot juice completed 19% more repetitions in total across the three sets [21]. So if you completed 20 reps per set, the beetroot juice may help you pump out an extra 3-4 per set. Not bad, but a lot more lackluster than the film portrays. There was also no difference found between groups for indicators for muscle fatigue.

The active component of beetroot that is in question is nitrate – a compound present in vegetables and is added to cured and processed meats (however, from a health perspective they are deemed safer from vegetable sources). According to research so far, nitrate may reduce the oxygen cost of exercise, potentially increasing exercise capacity [22]. This only appears to be the case for shorter workouts (e.g. HIIT), with less of an effect seen on endurance exercise >40mins. As exciting as this all seems, and although research is in very early stages, benefits have been seen with 5-9mmol nitrate per day – which is easily attainable with a balanced omnivorous or vegan diet, and there have been no observed benefits with any higher dosages which would require a supplement. Additionally, while evidence suggests a potential effect of regular consumption of nitrate on performance, effects of acute supplementation (as in the study used in the film) are much less consistent [23][24][25]. Some go so far to say it’s all speculation being hyped up by the supplement industry, while others warn that long-term nitrate supplementation could actually hinder physiological adaptations to training [26]. Realistically – we don’t know – so don’t go jumping to drink beet juice expecting amazing gains just yet.

Claim #8: Carbs for Muscle Building

A common theme throughout the film is that they tend to insinuate that veganism means high-carb while meat consumption means low-carb. In reality, the inclusion or exclusion of meat has very little to do with carb consumption. I’m confused too.

So here they cite a study that compared a ketogenic (very low carb) with a non-ketogenic (normal carb) diet to test which is more efficient for building muscle [27]. The group with a normal carb consumption came out on top. Okay, cool – what has that got to do with veganism? Well, in this case, absolutely nothing. Both groups in the study consumed the same amount of protein, both from – you guessed it – animal sources.

While yes, carbohydrate consumption is typically from plants, I don’t think there is typically a problem in the UK or US with eating enough carbs, unless specifically avoiding them by choosing to eat keto.

Claim #9: Burrito Experiment Number 1

This is probably one of the most talked-about clips. Dr. Robert Vogel, a preventative cardiologist, discusses the role of endothelial function on performance.

In this clip, three members from the Miami Dolphins each have a burrito: 1 vegan (black beans), 1 chicken and 1 beef. They then have their blood tested, which is centrifuged (spun around really, really fast) to separate the plasma. They repeat this the next day, but this time all three athletes eat the vegan burrito. On day one, the plasma fractions from the two meat burritos are cloudy from fat, while the bean burrito resulted in clear plasma. On day two, all the athletes’ plasma samples are clear.

My research on this has taken me down an extensively long and multi-channeled rabbit hole, so bare with; I’ll try and keep it brief.

It is well-accepted in the scientific literature that diet plays a key role in cardiovascular health, which is partly related to endothelial function (or dysfunction). Specifically, a Westernized diet (high intake of processed and red meat, sugar, fried food, refined grains) is associated with increased risk, while a diet rich in fruits and vegetables have shown to be beneficial for endothelial function [31]. I will not argue that a diet high in saturated fat is problematic and, as I have said before, an over-reliance on animal foods will likely mean high saturated fat intake. Saturated fat has shown to induce inflammation, resulting in endothelial dysfunction in the long term [32].

However, an unhealthy Westernized diet is not a fair comparison to imply that animal products are point-blank the problem. There is far more to it than simply the inclusion or exclusion of animal foods:

This highlights that it’s the overall composition of our diets that matters, and why focusing on only one aspect doesn’t give an accurate picture of health. Studies suggest that risk depends on (i) how the saturated or unsaturated fat is sourced and (ii) what we replace the saturated fat with (e.g. many studies have shown a protective effect if we replace saturated fat with monounsaturated fats, but not with polyunsaturated fats or carbohydrates [44].

The cloudiness of the plasma has to do with the presence of chylomicrons – particles that carry packages of fat particles in our blood immediately after a meal. Diets high in saturated or polyunsaturated fats are slower to remove chylomicrons (blood lipids) after a meal compared to monounsaturated fat – meaning that blood lipid levels stay elevated for longer [45]. Although it was traditionally fasted lipid levels that were thought to be significant for heart and endothelial health, recent studies show that postprandial (post-eating) lipid levels also play an important role [46]; so it is relevant for Dr Vogel to include this.

But while elevated blood lipids do play a role in endothelial dysfunction [47], I have to agree with others that it is a bit sneaky and that it was used to imply a more dramatic effect than reality. While there is a correlation between chronically elevated blood lipid, of which post-prandial lipids do play a role, and which is also associated with high intake of saturated fat, it does not mean that eating meat (or even eating an isolated meal high in saturated fat) means an automatic impaired athletic performance. Our bodies just don’t work that way. What I do believe is that eating a well-balanced diet, high in fruits and vegetables, healthy fats and low in saturated fat (which may or may not involve some level of inclusion of meat) is optimal for endothelial function and therefore athletic performance. Studies suggesting that plant-based foods can improve health markers do not conclude that animal products should be removed from the diet.

And since the film dismissed any study funded by animal industries – the study used in the film was funded by an avocado brand. Odd. It was also a pilot study in 11 people.

Claim #10: Burrito Experiment 2

More burritos – this time to challenge the idea that eating meat makes you more of a man. While I agree that masculinity and meat consumption are not related, the means by which they challenge this ideology is somewhat questionable.

Dr. Aaron Spitz says, “the more meat men eat, the more quickly they lose their ‘manly manhood‘ – great phrase, I’ll give him that – because, as “shown” in the previous study, meat inhibits blood flow through the entire body” (reminder: it doesn’t). Another three athletes are recruited for this “experiment” by Dr. Spitz (lead Urologist for the American Medical Association). After the uncontrolled giggling at the sight of a model of a penis (them, not me), Spitz explains that they will be studying the effect a meal has on their erection cycles that night. Similar protocol to the previous burrito experiment – first night, all three athletes are fed meat burritos (chicken, pork, beef); second night, plant-based burritos. Three erection measures are taken – frequency, duration and (*ahem*), firmness. Results were then handed out (cue more awkward giggling but I mean I would probably be uncomfortable talking about my penis’ functionality in front of my teammates too, not going to lie), and hey presto – meat makes your penis soft.

Dr Spitz himself highlights that this was not a scientifically valid study (he seems like a nice guy, I like him).

Claim #11: Effect of a Vegan Diet on Hormones

Claim #11a: Testosterone

Wilks then discusses testosterone levels in vegans and omnivores, accompanied by more flashes of scientific studies. Two of these images actually use the exact same study, but why not make it seem like more for fun? Anyway aside from that, the two studies referenced back up his claims that there is no statistically significant difference between vegans and non-vegans when it comes to testosterone [48][49]. Personally, I’m not surprised as I wasn’t under the illusion meat somehow elevated testosterone levels, but anyway there it is.

Little side note – there are other reviews inferring the opposite (that vegans have less testosterone than omnivores) – you are no less of the problem than this documentary.

Claim #11b: Oestrogen

The film then tackles the belief that soy products increase oestrogen levels. There’s not enough time in this post to go into this in detail so I’ll summarise – overall, the jury’s still out on the effects of soy in the diet, mainly depending on what population group and what aspect of health you’re studying. But generally, current science suggests you’re safe from soy lads [50][51].

The film then claims that the real oestrogen is in animal products, such as chicken and cows’ milk, and that it can increase oestrogen levels by 26% and reduce testosterone by 18% within 1 hour after consumption of cows milk [52]. This study was conducted in 7 men, and showed a temporary decrease in testosterone secretion. Yes, 7 men. Temporarily. Again, no lies, but definitely not accurate truth either. Although the levels naturally found in cows’ milk would not be high enough to impact human health, due to intensive farming and extended pregnancy in cows, oestrogen concentrations are higher (although studies show variations in the actual concentration in commercial cows’ milk). However, even with this increased concentration, the general consensus is that levels are still nowhere near what would be required to make a statistically or clinically significant impact. It’s interesting though, and I think is something worth thinking about. Intensive farming does no good IMO [53][54].

Claim #11c: Cortisol (the stress hormone)

Wilks also claims that “replacing animal foods with high carbohydrate plant foods reduces cortisol levels by 27%“.

Again, this is all clever wording; this is about high vs low carb, not vegan vs omnivore. The cited paper studied how protein:carbohydrate ratio alters cortisol levels; with a high-carb diet being associated with lower cortisol than a high-protein diet [55]. Nowhere does it mention the inclusion or exclusion of animal products. In addition, cortisol is not inherently bad. Cortisol is the hormone that readies us for fight or flight and is part of keeping everything in the body balanced. Chronic stress, generally induced by personal/emotional stress or over-exercising, leads to long-term excessive concentrations of cortisol which only then is then associated with negative outcomes on the body [56].

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