Oh, I understand. Eat steak, but don't eat steak. Thanks again, science.
Many low-carbers were quick to jump on this as a confirmation of what they've been saying all along, using this study as counter-evidence to the latest study which had opposite results. To be fair, the PURE study is, overall, a better conducted study: PURE had ten times the number participants and better design overall. But it's still an epidemiological study with all the limitations inherent to this type of science. It still relied on Food Frequency Questionnaires (FFQs) and can still only make claims about correlation, not causation.
It's the height of confirmation bias to reject one study on the grounds of its execution but accept one that uses essentially the same methodology but gets the results one likes (note that Malhotra was not doing this, but was simply pointing out that contradictory evidence, of the same type, exists). Ironically, the American Heart Association (AHA) issued a statement about PURE, warning of the limitations of FFQs. Perhaps they should apply that standard to the studies that justify their own dietary recommendations.
To get an idea of why you can't imply causation from observational studies take a look at my last article. In brief; you can't say that one thing causes another (such as saturated fat causes, or protects against, heart disease) by only observing the two things occurring together in the general population. To discover a causal relationship, you need to actually intervene, whether in a controlled environment or otherwise. So neither of these studies should be used as evidence of what constitutes proper human nutrition. Neither should be grounds for any recommendations at all, yet both study's authors have been widely quoted in the media doing just that. Here's senior author of the PURE study, Dr Salim Yusuf, and some of the other study authors, recommending dietary strategies based on their results. I guess they skipped Science 101 class the day this was covered.
So when I see two studies with contradictory results getting a lot of traction in the media, my brain starts working. The question that comes to me is why? Why would these two studies - both being used to give pseudo-science-backed recommendations - be circulating among many top media outlets? The first study, telling people that if they eat low-carb diets they're going to die earlier, is easier to tease out as far as motivations go - same old propaganda telling people to behave according to the Authoritarian Dietary Guidelines or they're going to die. The motivations behind publicizing the PURE study, however, is more tricky to put one's finger on.
I mean why, after fifty-freakin-years are we seeing alternatives to the standard dietary propaganda start to creep out to the public? The same scientific institutions that have been telling you if you eat so much as an egg your heart is going to explode for most of the planetary population's entire lifetime are now saying eggs, butter, cheese, steaks, pork chops - all the dietary evils of yesterday - are now GOOD FOR YOUR HEART! What are we meant to assume here, that saturated fat was bad for you in 1980 but in 2018 it suddenly became OK? Both claims were supposedly backed by Science. Either they were lying then or they're lying now (my money is on the former).
Maybe the dietary dictocrats have decided they've killed enough people with their backward recommendations and are going to try a different strategy of recommendations for awhile - telling people something a little closer to the truth. Maybe they've grown tired of the widespread suffering and health havoc they've loosed upon the world and are going to find some other way to spread chaos and destruction. Or maybe the pharmaceutical monopoly has a different drug in the pipeline for suppressing symptoms not associated with Big Food's brand of disease manufacturing, so they're moving on.
Keep in mind that there are hundreds of studies on various aspects of diet and health published every year, most of them getting little-to-no media attention. When one study gets a lot of traction in the media, carried by multiple outlets, it's for a reason. The reason is usually because someone has decided to put money behind it and push.
Spreading Confusion
In the Malhotra interview mentioned in the intro, the interviewer begins by saying "I'm so confused!" This is a natural reaction to the completely contradictory information being put forward by the press. Alcohol is good in moderation one day, a death sentence the next. Butter was the arch-villain, now it's the vindicated hero. The confusion of the public is palpable, and perfectly understandable.
To quote Daniel Kahneman "Slow, deliberate thinking is hard work. It consumes chemical resources in the brain, and people usually don't like that." In other words, people generally resist doing proper research on any particular subject to figure out what actually makes the most sense. So as a result, we tend to outsource figuring things out to others who have the time and inclination; the experts, if you will. And the mainstream media take on the role of spreading the word of experts, keeping your average worker drone free from having to peruse PubMed for answers.
But when competing expert views start to be promoted from these sources people get confused, and when they get confused, they get apathetic. Whenever the topic of any day to day conversation turns to a discussion of something health related, someone inevitably says something along the lines of "well, it seems like everything these days is going to kill you." It's become completely commonplace to be so dismissive, like saying "I don't really want to think about this because it will use chemical resources in my brain, which I don't like, so I'm just going to keep doing what I've always done".
Getting to the Bottom of 'Science'
But the way around getting to the bottom of the contradictory health information paradox is to fight the apathy and look beyond the headlines to find out if the claims being made stand up to scrutiny. This requires resources, and it's an expenditure few are willing to make. But if anyone has a penchant for truth and actually cares about their health and well-being, and that of their family, the cost in brain juice becomes less of an issue and digging in becomes more like a sport or a treasure hunt. Learning is fun!
So when you come across a headline talking about how "science" says that eating Cocoa Puffs daily will increase your life by 75 years, find out the type of study being reported on. Is it observational/epidemiological? Then any causal claims should be dismissed; it might be the case that Cocoa Puffs increase lifespan, but we won't know for sure until more rigorous studies are done. Is it a controlled trial or some kind of intervention? That's better evidence (although still not foolproof). Is the study done on mice, rats or guinea pigs? That might be pretty good evidence, but one needs to remember that humans aren't guinea pigs (in the literal sense, anyway). Findings from animal studies may provide some clues, but we don't really know if they apply to humans until someone does the same trial on humans.
That's the basics on study literacy, but there are lots of other tricks played, both by the media and by the scientists themselves, to make studies appear to show results that can't really be generalized to everyday life. One trick, like in the "low-carb-will-kill-you" study, is to label a diet "low carb" or "high fat" when closer analysis reveals the diet eaten by the subjects in no way resembles the diets eaten by people specifically doing a LCHF (low carb high fat) diet. 'Experts' do this in rat studies all the time, feeding the rats a standard high-fat rat chow that is also very high in carbs (not to mention all the chemical crap in the mix), but conflating their results with human "high-fat diets". If someone is trying to convince you of something about LCHF diets and the animals in the study were fed rat chow, those results say nothing about anyone eating real food. It pays to look into what the subjects in the study were actually eating.
Researcher will also explain away their results, or spin them in a way not congruent with the findings, in the abstract of the study. Sometimes this is done for political reasons. In order to get published, authors often find themselves in the position of having to submit to the dominant ideology and need to spin their results in such a way as to not contradict the status quo.
Other important factors to consider are the length of time the study covers, how they're collecting their data, how they're measuring their variables, the population being studied as well as who funded the study and any possible conflicts of interest among the authors (i.e. who's paying them for anything, now or in the past).
Many of these mentioned factors aren't necessarily deal-breakers. In general, studies aren't usually just 'good' or 'bad', but lie along a spectrum of veracity which give hints on how much weight should be given to their findings. A randomized controlled trial (RCT, considered the gold standard for research) should have more weight given to it than an observational study.
But other factors should be considered besides just studies to form a mosaic of information that give us an overall picture. Common sense should rule here, although it's in short supply these days. History is important, both in terms of 'how long have humans been eating X?' and the history of past research on the subject. It's also good to know if there is a known or hypothesized biological mechanism for the results shown and whether the results are reflected in other populations.
If health and science reporters in the media were actually educated in what they're writing about, and not just rewording press releases and news wire services, they'd be fulfilling this function for us. But they give the same amount of clout to every study that comes along and suggest people act on them. Ideally, any credible researcher would point out the limitations of their research when speaking to the press (and some of them do). But unfortunately, in the current click-bait, headline-grabbing climate, the exact opposite is true.
Despite the fact that the PURE study really isn't great for showing the effects of a LCHF diet, take a look at some studies that are great. The Diet Doctor, Dr. Andreas Eenfeldt, has amassed a number of studies showing the benefits of LCHF for everything from weight loss, type 2 diabetes, heart disease, cholesterol, and much more. Similarly, Sarah Hallberg over at Virtra Health has created a comprehensive list of low carb research in a Google Doc accessible to the public. Both these sources list the types of studies and additional information for quick reference.
In my childhood, every time my mother and her sister met (they live some way off each other), they started going on low-calory diets because they were displeased about their weight. They tried everything, but even though there was weightloss, it soon came back... and then some.
Now, some of my colleagues are running on treadmills like hamsters, trying to consume more calories than they eat. I tell them that every single "jogger" I know of has died of a heart-attack, and that if you don't consider very carefully what you eat, this type of weight control is very dangerous.
I must say, though, that of the success-stories I know of, the common causal factor is taking control of the diet. To not eat industrially mass-produced ready-made foods at all. I have advocated for going cold turkey on grass-based foods (crops, corn, rice, sugars), but doing so is very difficult and requires a lot of your money and time - as you will have to make everything yourself, from raw materials. It is a very "intrusive" life-style change, and therefore very difficult to pull off. But now I am thinking that this might not be necessary at all.
If you take the time, money and effort to be 100% sure that what you put in your mouth is good for you, the data seems to show (in this article as well) that there are health benefits from both LCHF and vegan lifestyles, and anything in-between. If you don't know what you're doing, however, these lifestyles can both be very damaging.
The common factors of what all these diets do that lead to health benefits seems to be knowledge and self-insight, not the diets themselves. All the data shows that well-educated people tend to have better health and live longer than less well-educated people, and the common factor there (other than money!) is that the former are going to be better at researching for themselves what is good for them.
So I have come to the conclusion that if I don't eat vastly more calories than I burn and have a balanced, home-made-from raw-materials diet of fish, meat and vegetables - avoiding too many fast-burn carbohydrates since I don't work out that much... then I'll be fine.