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Reeling from some more groundbreaking, shocking, and controversial dietary research, or are we? This week's publication of five separate items of research concerning the consumption of red and processed meat: are they helpful, or just further confusing people who are already bombarded with contradictory messages? I wanted to get this video out quickly. I'm already a couple of days late because I was traveling and had quite an eventful plane journey, so please excuse the fact that this is shot in a random room. I'm in Kolkata, which is hardly the quietest of cities, so it's a bit noisy. I've had to turn the fan and the air-conditioning off just for you, so I'll probably dissolve in a pool of sweat. This video is going to be quick and dirty, rather like how I have my burgers. But should those burgers be meat or veg?
Unfortunately, there's a lot of tribalism that infects dietary discussions, so if you're a hardcore vegan or a carnivore supremacist, this video probably isn't going to be for you. However, if you are someone who's genuinely interested in the science and wants a neutral view, hopefully I can offer a bit of help. I have no conflicts of interest. I'm not selling a book or a diet plan, I'm not on the payroll of Big Moo or the Carrot Conspiracy, and I am not a member of any food-related group or tribe, except maybe the Order of Honourable Taramosalata Fanatics. I mention all this because it's intriguing to me how different groups cover the exact same research in different ways. The carnivores say it supports them, the vegans say that the research is wrong. So let's take a look.
We'll start with a summary of what the research showed. This was actually five simultaneous publications. The first three were meta-analyses of observational studies with a minimum size of a thousand people, and all of them put together, which is over a hundred, I think, is starting to look at six million people, so this cannot be accused of being small. But these are observational studies, remember, and they looked at the big three: death, cardio-metabolic disorders, which includes heart disease and diabetes, and cancer. The next paper was a meta-analysis of randomized controlled trials, which are much higher on the ladder of reliability and quality of evidence, and they looked at 12 randomized controlled trials with a total of 54,000 people, but this was really dominated by one study which was 49,000 strong. There was also a set of guidelines published, which we'll talk about a little bit later, and one of the publications was looking at attitudes really to do with meat-eating, which was very interesting but not really related to health outcomes, so I won't talk about that in this video.
The observational meta-analyses actually showed nothing new. They revealed that over this large group of people, reduction in red meat consumption and processed meat resulted in a very small benefit in terms of the big three that I mentioned earlier. I've talked before about absolute versus relative risk reduction, so don't be fooled by studies that say your risk is halved, because if your risk is only 1% to begin with, then your actual real benefit is fairly negligible. For example, in real terms, what these studies show is that red meat reduction was associated with four fewer deaths from heart disease out of a thousand people over 11 years. These small population-wide benefits mean very little to an individual looking to see if she or he should change their dietary habits.
You might assume that if I've just said that reducing red meat consumption causes a very small benefit, that means everybody who does it will derive a very small benefit, but that's not how this works. It's actually the same concept behind why statins are so unpopular. Both reducing red meat consumption and taking a statin for primary prevention mean the vast majority of people who do those things will actually derive no benefit, but a very small number will derive a very large benefit. In this case, probably around four people out of a thousand over 11 years.
But observational trials in diet are notoriously unreliable, primarily because of endless confounders, a reliance on self-reporting, the fact that you can't attribute causality in an observational trial, and looking for rare events that occur over long periods of time, like high blood pressure leading to a heart attack, which need huge numbers and a very long period of follow-up. One way to increase your signal-to-noise ratio in your favor is to only follow up patients who are already at high risk of developing these problems, and that's what the PREDIMED study did, which is a whole other debate. A study that was published, retracted, and republished with modifications, I don't think it was really part of this analysis anyway. But what that does is, if you take an at-risk population, that means your findings might not be transferable and attributable to the wider population, because the majority of people reading this dietary advice are healthy. We've talked about selection bias already on this channel a few times, so if you ask me, observational studies in diet are pointless and we should just stop doing them.
So let's concentrate on the randomized controlled trials, or RCTs, although these are also very challenging in dietary research. The analysis of twelve RCTs, which, as I said, was dominated by one, showed that there was no relationship between the consumption of red and processed meat and adverse health outcomes. This is certainly what the press has picked up on in a big way, because the authors themselves have weighted the findings from RCTs more heavily than those from the original studies, which seems quite fair enough to me, but make up your own mind. However, I want to highlight one key thing. The authors themselves, and I'm going to quote directly, said that their conclusions were based on low to very low quality evidence. This is a key piece of information that I feel has been a bit lost in most of the news stories that I've read.
The critics of the research are numerous and from very prestigious backgrounds. They include the American Heart Association, the former president of the American College of Cardiology, the American Cancer Society, Harvard Medical School, the Physicians Committee for Responsible Medicine, and if you really have any sense, you'll pay much more attention to them than some clown on YouTube. But are their criticisms valid? Many of their critiques could be leveled at pretty much all dietary research. As we've already said, observational studies in diet are basically trash, so in terms of quality of research, this is about as good as it gets, so I don't feel that criticism is justified. The fact that real experts in the field can look at the exact same data and draw contradictory conclusions may mean that they're biased. I don't think that's the case here. I think in this case, it's a reflection of the fact that the signal is so weak that it's hard to draw any definite conclusions.
A fairly convincing argument could be made for saying that there's sufficient doubt to mean that you should stick to the current dietary advice, and certainly at the moment, all the major health organizations recommend reducing red meat. However, one could also now make a counter-argument to that, which would be fairly compelling as well. I think the medical profession makes life difficult for itself when it starts trying to suggest a numerical value for how much red meat you should reduce, or how many helpings of processed meat you should eat per week, what is too much, because these figures would essentially just be plucked from the air. They're not based on anything.
One of the main criticisms from the group, Physicians Committee, seems quite reasonable, which is objecting to the guidelines that are drawn up as part of the publication, which are essentially made by a self-appointed panel. That's a bit unusual in medicine, particularly in a controversial area like this. Anyway, the main message from those guidelines is that people should not change the amount of red meat they're eating unless they want to, because there isn't really the evidence to say one way or the other, which, if you want to really look at all the work they've done, is a fairly reasonable conclusion.
So, one of my take-home messages from this very large amount of new research, well, to be honest, not a great deal. By the authors' own admission, the conclusions are low to very low confidence. I want to stress that point again. But let's assume that the findings were watertight and 100% reliable. The evidence before all of this showed that reducing red meat intake produced very small health benefits, and that hasn't changed. The evidence before all of this was published said that you will derive far more benefit from taking up regular exercise or stopping smoking than you will from reducing red and processed meat, and that hasn't changed. The evidence before all this said that you will derive more benefit from cutting out the bap, the Coke, and the chips that you have with your burger rather than the patty itself, and that hasn't changed. The evidence before all this was published said that having a balanced and varied diet was healthiest, and that hasn't changed. There's nothing in this new research to support the exclusion of vegetables from your diet, and there's plenty of research showing that vegetables are beneficial. So unless you're eating salami three times a day, you're better off addressing these other things than worrying about how much red meat you consume.
I don't like adding my own personal commentary to these videos, but I always seem to get loads of comments asking what I do, or whether I've tried a certain thing, or what my own experiences are, so I've saved it to the end. For those kinds of people who are interested, I do eat meat, but I have drastically reduced the amount of meat of all types that I eat in recent years. The part of the research that I didn't talk much about, the one about attitudes to meat-eating, said that people like me, omnivores who are told to reduce their red meat intake for health reasons, don't really pay a lot of attention to that. But for me, understanding the environmental impact of the meat industry, particularly beef, was a real eye-opener. Unlike the health reasons, as I think I've covered, the environmental reasons are far more scientifically robust. Plus, vegetarian options have really improved recently. In the last week I had a Five Guys burger, and the next day I had a Lian vegan burger, and they were both great. And out here in India, one of the few countries where the red meat research really isn't big news, and in fact in certain parts of the country eating beef can definitely result in an increased risk of dying, there are so many fantastic vegetarian options and alternatives to meat that you really don't miss it.