That’s a question I have been asked many times over the past 2 months. I’ve also pondered this choice a few years ago after reading Scott Jurek‘s book Eat & Run and more recently after watching the Netflix documentary “The Game Changers“. The underlying message from both Eat & Run and The Game Changers is that eating an all-plant diet is “healthier” for athletes and provides better recovery after training or racing, translating in potentially stronger sport performance over time. What’s not to like here?
Luckily Karina has been studying nutritional science and has access to existing peer-reviewed research papers. The conclusion is clear: there is no evidence from the scientific community that eating an all-plant diet is either “healthier” or provide better recovery. That said it does not mean that it’s not the best option for some people. It’s quite clear from existing research that each person has unique nutritional needs based on his/her genetic make-up, environmental factors, gut microbiome, immune reaction to certain food, etc.
There is also an ethical/environmental component to eating an all-plant diet but that was not the primary reason I got intrigued nor the underlying motive behind most of the questions I received on this topic so I’ll focus here on the health & sport performance aspect as I have not done enough research to have an informed opinion on the environmental impact & the ethical aspect is a very personal topic I’d prefer not to discuss via a blog.
I’ll come back later to why I don’t think “The Game Changers” or Eat & Run are likely credible sources to make a decision.
This question made me think of the more general issue: “Whom/who can I trust?” or how are we, non-expert, supposed to differentiate among the cacophony of conflicting “expert” opinions. For example, I’ve recently wrote a post on the Wim Hof method – why do I trust Wim Hof and not Jurek/Gamechangers?
I clearly don’t have the definitive answer of such a thorny problem but I’ll share below the some of the screens I have developed over time.
The first step is to assess the range of existing opinions and subject-related uncertainty. In some fields like in physics or mathematics, there tend to be a narrow range of expert opinions, while for others such as physiology, nutrition, economics, there is a wide range of expert opinions. The latter fields are often related to dynamic, complex systems with significant non-linearity and emergent properties. To state the obvious, when dealing with a wide range of expert options, it’s time to switch on the bullshit detector.
The second step is to look for some of the classic techniques used by non-credible sources to make their arguments:
Testimonials: testimonials tends to be red flags because they tend to involve small samples that can’t be generalized, especially given the complex nature of the underlying system (e.g. human body). Testimonials are also often fake or exaggerated to begin with. They play on the human’s love for drama & success story.
Assuming a causal relationship where there is none – you’ve probably heard of the advice “swim to develop long, lean muscles” mixing the fact that people with long/lean muscle are more likely to excel at swimming vs the activity of swimming making long/lean muscles.
Citing a specific scientific study – the scientific argument is often used to give credibility. Scientific studies & research paper can be biased and sometimes the statistical analysis is just wrong. Looking at the paper itself and who finance it is paramount and one needs a lot of converging studies to start having a reliable conclusion.
Then I look at whether the phenomenon in question has survived the test of time (“the Lindy Effect“) and whether I can understand the mechanism. Let me explain.
Is coffee bad for you? People has been drinking coffee since at least the 15th century in Ethiopia and its use has been spreading geographically so it has passed the test of time on a large enough sample of people than I feel fairly confident it’s unlikely to have nasty consequences as long as I consume a reasonable quantity that feel good and nothing strange is added to it 🙂 Obviously some people are more sensitive and metabolise coffee faster than others.
Why do I trust the Wim Hof method? First, the breathing technique is very similar to the Tummo breathing technique used by Tibetan Buddhist in India since the 8th century and later incorporated in Kundalini yoga practiced by million of people. Furthermore, the exposure to extreme cold / ice-baths has been an ancient practice used across centuries in Nordic countries. Second, I understand the broad underlying mechanism, called hormesis, making the body more resilient. Third, Wim Hof has been willing to engage with the scientific community to conduct tests and unravel the exact mechanisms. Does that mean that we fully understand what’s going on and that there is no significant placebo effect happening? Of course not! but in my view there is enough evidences to justify investing my time and taking the limited risks practicing the technique.
As an aside, the problem of finding reliable sources of information is a key issue in investing too. The amount of “experts” with widely diverging view in macro-economics for example is stunning. The issue arises also in selecting fund managers or operating partners based on past track record. In my experience, understanding the mechanism/process (i.e., team, investment strategy, edge, etc.) by which the past results were achieved is key but often difficult.
Now, back to the all-plant diet. We are clearly dealing with a field where there is a wide range of opinions – all-plant competes with experts recommending all-meat, keto, no carbs, etc. All-plant diet has endured the test of time so it’s unlikely to be dangerous but there is no evidence that these populations were healthier or more athletic than population eating a Mediterranean diet for example. Scott Jurek is a legendary ultra-runner, however that’s a sample of one and I couldn’t find many others endurance champions following all-plant diets. It’s worth noting that before becoming vegan he was eating mostly process food so it’s not too surprising he felt much better with a vegan diet.
The Game Changers documentary enlists all the techniques listed above; stories from an impressive list but limited number of current & former athletes and “cutting edge” pseudo-science but overall it seems to be light on real evidences.
So on balance I could not find enough evidences to seriously invest the time & take the risk to switch to all plant diet. Common sense would suggest that Mediterranean-type diet works best for me; and guess what? It does 🙂
Thanks to Karina, I mostly focused on eliminating foods that clearly did not work for me because of allergies or intolerance such as lactose. I’d encourage everyone to do few main tests related to food allergies, immune reaction, and gut microbiome composition. From time to time, I also use diet periodisation whereby I combine specific training protocols with certain type of food to create a specific stimulus – for example, low intensity training with low carb, high fat to improve fat metabolism. Finally, I naturally use intermittent fasting when I go for a long run in the morning on a fasted state.
Keep questions coming and as always I’d love to hear from you if you see the world differently!