The "creativity" behind the vegetarian diet.
Even the most distracted have noticed the increasing and more intense appeal to adhere to a vegetarian diet (or any of its variants) using various science-based arguments, from sustainability to the incredible benefit they claim to have for our health, performance and longevity.
Anything that can have that impact attracts my attention:not only am I always looking to improve my own performance but also to build the most correct and effective plans and protocols to those who seek us out to be healthier. Whenever some strategy claims to be able to do so, I try to find out more and what science supports it.
In particular with regard to the vegetarian diet, there were three reasons to do so in a more elaborate way:
As far as the macro-nutrient composition is concerned, the vegetarian diet is diametrically opposed to the one that made me lose my more than 50kg: it is composed mostly of carbohydrates while the most suitable plan to defeat obesity is a low-carb strategy.
During my consultations, I began to notice that a significant percentage of vegetarians / vegans felt an initial significant improvement in their energy and vitality, but after a few weeks, they felt a drop again - coupled with a change in bowel function.
World references in the area of longevity, performance and health, such as Dr Peter Attia, Dr Tim Noakes and Ben Greenfield advocate other nutritional strategies for those who want to live longer and better, leading to my first conclusion: there is definitely no consensus that it is the best option. These are individuals who spend their lives evaluating published science, they even have teams of researchers at that task. Even Dr Tim Noakes' public change of heart regarding carbohydrates and fat is well known.
I wanted to "see for myself" - to read and interpret - the arguments presented and decided to read one of the most proclaimed books in this thread: "How Not to Die" by Dr Michael Greger. Could I have read one of the many articles available online? I could have. But it wasn't the same. I didn't want to read someone else's filtered opinion, I wanted to form my own and come to my own conclusions.
The book itself is a compendium of over 600 pages, of which over 150 are the numerous references used throughout the text. In fact, this is one of its merits: it is almost impossible to find a paragraph that does not contain any scientific reference, making detective work more time-consuming but enriching and fun.
On the other hand, it becomes much easier to find surprises and, let's say, creative solutions...
I should say that at the time of writing this article I have not fact-checked the whole book, having focused on the cardiovascular and weight management areas. Perhaps my conclusions will be different when I read the whole book and if that happens, how to believe I will share them!
Having said that, let me say that it is necessary to really want to show that the vegetarian diet is the best option to say that there is irrefutable evidence to prove it, as it is said right at the beginning of the book. Only a really big will can make someone say that, since it is absolutely wrong.
I find three key problems in the studies that Dr Greger refers to in the book or in the way he portrays the evidence:
1) Healthy User Bias
The vast majority of the key studies described in the book suffer from so-called healthy user bias. This bias intends to describe the fact that those who follow a vegetarian diet will almost certainly take more care of their health. Your food choice will mean that you should have a greater desire to be healthy and want to follow the indications given by your doctor (taking into consideration the indications that have existed since the 1970s, which were born in a "strange" way. Read this other article of mine to know the origin of the food pyramid).
For the same reasons, this person should also have a healthier lifestyle, in particular be less sedentary, exercise more, drink less alcohol and smoke less. They should also choose foods with better nutritional value, opting for organic products. In addition, they are also likely to take greater care with stress management (with frequent meditation and yoga practices) and belong to a community.
The same reasoning goes the other way too: overall, non-vegetarian people will be more likely to eat less carefully, smoke more, drink more alcohol and be more sedentary.
All these factors increase the risk of chronic disease and have a major impact on your health.
Studies that compare "vegetarians" with "non-vegetarians" and do not take this bias into consideration cannot be used as arguments in favour (or against, since the flaw in the argument is the same) of the vegetarian diet because it is not possible to isolate this effect.
Examples are the studies in which "non-vegetarians" are compared with elements belonging to the Seventh-day Adventist Church. This is a population that is used a lot because they are forbidden to eat animal products, in particular meat. Throughout the book these studies are used to say "Do you see the effect that not eating meat has on health? Just look at these people!".
They also happen not to smoke or drink alcohol, exercise is encouraged, and there is a sense of belonging to a very large community (perhaps because of this, they have lower stress levels), something the "non-vegetarian" group is unlikely to do. Any of these habits are associated with higher levels of health, and it is not possible to attribute them to one or the other.
Despite Dr Greger's willingness, observational studies that do not account for the effect of healthy user bias cannot be considered as scientifically advocating a vegetarian diet.
2) Impossible comparisons
Unlike many other clinical areas, research in the field of nutrition is extremely complex because it is very difficult to keep track of what an individual eats 24 hours a day for the duration of the study - weeks, months or even years. The vast majority use'food frequency questionnaires' in which you record how often (or even how much) certain listed foods were eaten.
Not only is this method unreliable because it relies on participants being able to accurately describe what they have eaten, it is also influenced by the way foods are characterised and listed. A great deal of creativity can be given to determining the categories, greatly undermining the reliability of the studies used by Dr Greger.
Let me ask you this question:
Do you think it is fair to include in the same category "vegetables" broccoli and chips in a fast-food chair? Or within the category "cereals" organically produced whole wheat or pre-packaged wheat flour? I assume you think not because their nutritional value and health impact is not comparable. Most researchers agree with us and are very careful: they include broccoli under "vegetables" and whole wheat under "cereals" but include wheat flour and crisps under "processed foods". So far so good.
Now, do you consider that eggs, fish and meat are the same? Or even that the meat served in a hamburger chain is similar to a steak from a grass-fed cow? Yeah, I don't think they're the same either. You know who doesn't agree with us? Study planners! In the vast majority of cases, anything that is an animal product, from fish, eggs, dairy products or meat, including highly processed meat, falls under the category "meat". Does that sound scientifically fair to you?
Isolating the healthy elements of the "vegetables" and "cereals" category and not doing the same with "meat" makes any comparison wrong and even impossible to make.
3) Extrapolation of results
There are few intervention studies in the area of nutrition given the technical difficulty of controlling what participants eat. So, whenever any emerge, they are given a lot of attention.
This is what happened when Dr Dean Ornish published articles saying that he had managed to reverse coronary heart disease in participants in studies conducted at his clinic. Regardless of whether some argue that the method used to assess the extent of the disease is not conclusive, what is certain is that there is published scientific demonstration that his therapeutic protocol achieved this wonderful impact. Highly commendable, no doubt.
Dr Ornish's success was quickly used as an "irrefutable" argument to show that a vegan diet with extremely low fat levels were the key to the drama of coronary heart disease. And it would have been fine if the only intervention undertaken had been the dietary strategy. But there is always a "but"!
And this 'but' is that in addition to the dietary intervention, participants were subjected to an intensive therapeutic plan that also included total avoidance of tobacco and alcohol, daily exercise and mindfulnessto manage stress and promote a sense of belonging to a community.
If it is possible to say that Dr Ornish can reverse coronary heart disease, it is not possible to isolate any one of these factors, be it diet, exercise or mindfulness (each of which has widely published benefits). It is as true to say that it is the low-fat vegan diet that is responsible for the results as quitting smoking. I leave the provocation: which do you think is more likely?
Now, does this mean that people who adopt a vegetarian diet and feel much better, stronger and healthier are imagining it or are they mistaken? Of course not! I am not at all surprised that this happens. In fact, I would say that it is very likely to happen!
The reason is simple:
The benefit is not in what they are eating, but in having stopped eating what they were eating!
Which seems healthier to you, a fried steak with chips and fried egg, all cooked with vegetable oil of dubious quality, or a salad with different vegetables of different colours, drizzled with olive oil? Certainly the second option. If you make this substitution and start to feel better, more energetic and healthier, is it possible to attribute this effect to the salad or to having stopped eating "badly"?
Anyone who replaces a so-called "Western" diet, or in one way or another the usual diet of today, will automatically significantly reduce the amount of refined foods, poor-quality processed meat or fast food and will increase the consumption of vegetables and fruit, which will automatically translate into nutritional and metabolic benefits.
Even just swapping processed meat for grass-fed meat will already have that impact! Furthermore, along with that change you will probably adopt other healthy habits such as increasing exercise or reducing the amount of alcohol (it's hard to improve one area of our lives while leaving others the same), contributing to the overall improvement in health and well-being.
This argument applies to anyone in any context, including the super athletes featured in the documentary Game Changers. The question is the same: was the impact they felt on their performance due to their new diet or to leaving their old one? It is an answer that is left unanswered throughout the documentary - and in the debates where the vegetarian diet is discussed.
I hope I have helped bring some light to this discussion and that you feel more informed and ready to make better decisions.