The Game Changers – Should You Change Your Game? Part 2

Dr Warren Bradley PhD, Lauren Halsey, Tim Clarke and Paul Harter
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In the second part of our response to the hit Netflix documentary “The Game Changers", we take an educated look at three key nutrition points: protein, micronutrients and dairy. As promised, here we reveal the evidence that Game Changers leaves out of their narrative. Keep reading to discover the real truth about changing your game...

Adequate Protein

Game Changers points out that athletes need carbohydrates, not protein, for energy. That is correct. But, everyone needs protein to repair and maintain strength and lean muscle mass (as well as to optimise hormone production, including sex hormones). Game Changers then tells us people don’t need animal sources of protein, and to prove the point, they parade vegan strength and endurance athletes, claiming that they get more than enough protein from plants. The truth: athletes can easily get sufficient protein from plants. Office workers often cannot. It’s simple arithmetic. Allow us to explain:

Currently, scientists generally concur that people optimally need 1.2 to 2.0 grams of protein per kilogram of bodyweight per day. At 2.0 grams, a person weighing 80 kilos needs 160 grams of protein per day. An 80-kg endurance athlete could be expected to burn 6,000 kcal per day (and therefore need to eat around 6,000 kcal per day to maintain bodyweight -- neither gain nor lose weight). A sedentary 80-kg office worker could be expected to burn 2,000 kcal per day (and therefore need to eat 2,000 kcal per day to maintain bodyweight).


Let’s look at plant-based sources of protein:



Protein per 100 grams

Kcal per 100 g

Protein per 100 kcal


9.0 g

116 kcal

7.8 g


2.8 g

34  kcal

8.2 g

Kidney Beans

14 g

220 kcal

6.4 g


10.6 g

94 kcal

11.3 g


And grilled chicken breast:


Chicken breast

31 g

165 kcal



So, to consume 160 grams of protein from just one of the above sources:



Grams of Food for 160 g Protein

Kcals for 160 g Protein


1,777 g

2,061 kcal


5,714  g

1,943 kcal

Kidney Beans


3,172 kcal


1,509 g

1,418 kcal

Chicken Breast

516  g

851  kcal


You’re a vegan athlete eating 6,000 calories per day. It’s pretty easy to get adequate protein from plants. You’re an office worker eating 2,000 calories per day – it’s considerably more difficult, unless you’re prepared to eat 5.7 kilograms of broccoli or 1.7 kilograms of lentils per day (or else increase your daily calorie consumption, and gain a lot of weight). We can quibble about whether the optimal protein consumption is 1.2 grams or 2.0 grams per kilogram bodyweight. We can quibble about whether the athlete actually burns 6,000 kcal today or somewhat less than that. But the point we make is clearly demonstrated using any reasonable, realistic set of variables.

Adequate Vitamins and Minerals

Despite numerous health benefits associated with plant-based foods, eating just plants at the exclusion of whole food groups such as meat and dairy, can quite rapidly result in nutritional deficiencies.1 Hundreds of studies have illustrated the negative impact on the body associated with nutrient deficiencies,2 many of which have been conducted with vegetarians and vegans. Imagine trying to ride your bicycle without regularly oiling the chain. It would still work (for a while) but it would begin to show signs of wear and eventually grind to a halt. 

Nutrients such as Vitamin B12 and creatine are found almost exclusively in meat and dairy, whilst others such as Iron and Calcium (to some extent) are found in small quantities in plants, but are significantly less bioavailable (less able to be absorbed by the body). Some grains, legumes, nuts and seeds also contain compounds called phytates that block nutrient absorption (such as Iron), meaning more nutrients need to be consumed for adequate absorption. This may be tricky when foods contain low concentrations of these nutrients and have a lower bioavailability in the first place. 



Let’s look specifically at Vitamin B12, Iron and Calcium.

Vitamin B12 is involved in the metabolism of every single cell in the body. It is probably the most important deficiency resulting from plant-based diets.3 Vitamin B12 is found in wild fish, eggs, grass-fed beef and dairy products. Although it is found in an alternative form called cobamides in sea vegetables, algae and seaweeds, the bioavailability from these sources is particularly poor. So, regardless of what you choose to eat within a plant-based diet, this nutrient will rarely reach optimal levels without supplementation. 

Iron is required for oxygen transportation in the bloodstream (haemoglobin) to the cells. Deficiency results in anaemia, fatigue, low sex drive and becoming short of breath as your body attempts to increase oxygen delivery to the cells. There are two different forms of iron: heme and non-heme. Heme, found only in meat, is highly bioavailable,4 whereas non-heme, found in dairy, eggs and plant foods, is much less bioavailable. Dark leafy greens, nuts, seeds and legumes contain relatively high amounts of non-heme iron, but legumes also contain phytates which block the absorption of nutrients such as iron. So, go easy on the beans if you want to absorb your iron!

Calcium, found predominantly in dairy, is essential for the development and maintenance of the skeleton, and also for heart, muscle and nerve function. Deficiencies are associated with numerous osteo (bone) issues such as osteoporosis or ‘brittle bones’ resulting from very low bone mineral density.5 In a study of 1475 adults, vegans had significantly lower calcium intakes than vegetarians and omnivores, and fell short of national recommendations. Findings from a meta-analysis of several studies on Calcium also predict a higher risk of bone fractures in vegans. Although found in dark leafy greens and fortified soy products, adequate daily consumption of these foods is required to avoid deficiency, and therefore supplementation may be necessary.6


Game Changers vilifies dairy. However, they ignore the many studies that show an association between dairy consumption and positive health outcomes, including improved blood lipid profiles and a reduction of the risk of cardiovascular disease7 and improved insulin resistance and a reduction of the risk of type II diabetes.8

Yes, some people are lactose intolerant. Most people are not. Though our hunter/gatherer ancestors did not consume milk products after weaning, in the 12,000 years since the beginning of the agricultural revolution most humans have evolved to be able to digest dairy and include dairy as a healthful part of their diet. Many indigenous populations, such as the Masai, consume large amounts of dairy, yet live largely free of the age-related diseases that plague the Western world.

Game Changers is the next instalment in the crusade to get people to stop eating animal products, written by people who believe that the ends justify the means. While their goals may be noble, their methods are not. There is a lot to be said for eating a predominantly plant-based diet, whether or not you also include some animal products in your diet. Healthy veganism takes discipline and hard work. It’s a personal choice each of us can make for ourselves. 

Veganism is an ethos for living, not a product to be bought and sold. It goes beyond what you eat and includes all aspects of the human relationship with animals and the environment. Vegans have no need for Game Changer’s sensationalism to justify their moral choices. And conversely, that very same sensationalism fuels reactive anti-veganism, which is equally unhelpful. If you are confused or need help deciding what’s best for you, consider consulting an expert who knows the science and is free of personal agendas.


1 Derbyshire (2018); Larpin et al. (2019); Sanders (1999)

2 Larpin et al. (2019)

3 Pawlak (2013)

4 Valenzuela et al. (2009)

5 Lanham-New (2008); Smith (2006)

6 Larpin et al. (2019)

7 Warensjo et al. (2009); Elwood et al. (2004); Bonthius et al (2010).

8 Mozaffarian et al. (2010)



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