Monday 19 July 2021

The Pioppi Diet is a superficial lifestyle guide based on distorted evidence

First published by Spectator Health in July 2017

Pioppi is a very small village in southern Italy. It is one of those places where people are reputed to live much longer than average (the authors claim life expectancy is 89 years but do not provide a citation for this claim). The gimmick behind this book is that the authors have travelled to the village, bottled its secrets and are prepared to sell them to you for a small fee.

Since the authors are both advocates of the low carb, high fat (LCHF) regime, everything is seen through the prism of the Atkins diet. They are Aseem Malhotra (a cardiologist, as he never tires of reminding you) and Donal O’Neill (director of internet-only, anti-carbohydrate movies such as Cereal Killers and Run on Fat).

In some respects, Pioppi is a surprising place to find this low carb duo as it was the home of the scientist Ancel Keys who died in 2004 at the age of 100. It was Keys who drew the world’s attention to the villagers’ longevity when he was conducting research into nutrition in the mid-twentieth century. That research helped to create the evidence that linked saturated fat to heart disease, and low carb activists have spent years portraying him as a crackpot and a bully who was probably in the pay of Big Sugar and who definitely blackmailed the scientific community into unfairly ‘demonising’ saturated fat. As a result of his junk science, they say, governments around the world changed their dietary guidelines to encourage the consumption of carbohydrates at the expense of life-saving lard. The general public, slavishly following government advice as always, took this as a green light to stuff their faces with sugar and soon became obese.

It’s a bizarre and ahistorical conspiracy theory which, as Anthony Warner says in The Angry Chef would require ‘paying off the medical establishment, the World Health Organisation, numerous charities, public health bodies and nutrition researchers around the world, and keep producing systematic reviews that show links between consumption of saturated fats and increased risk of heart disease.’ The idea that millions of people have been killed by guidelines which (a) were never followed, and (b) clearly discouraged sugar consumption, is one of the strangest memes in the world of nutritional woo.

Pioppi is at the very centre of the nutritional orthodoxy. Not only did Ancel Keys live there for many years, but it is recognised by UNESCO as the home of the Mediterranean Diet. In a sense, The Pioppi Diet is an attempt to erase the legacy of Keys and reclaim the village for the one true faith of LCHF. Keys attributed the Pioppi residents’ low rates of heart disease to the relative scarcity of saturated fat in the Mediterranean diet, but as far as Malhotra and O’Neill are concerned, saturated fat has been exonerated and their job is to discover what is really going on there.

Reading between the lines of The Pioppi Diet, it’s reasonably obvious what’s going on. It’s a rural farming and fishing community of 200 people who are engaged in manual labour from a young age and remain physically active throughout their lives. The air is clean and the local diet is dominated by fruit, vegetables, fish, pasta, olive oil and wine. The villagers have traditionally been too poor to eat a lot of red meat. Indeed, they have been too poor to eat a lot of anything, hence the low rate of obesity and its associated diseases.

The longevity of the Pioppi people is therefore entirely consistent with mainstream science and yet it forms the backdrop to a book which tells the reader to be ‘prepared for everything you know and believe to be true to be turned on its head’. But it is only a backdrop, a blank screen onto which they project whatever thoughts come to mind. They visit the village but do not conduct any research there. Instead, they stroll around drinking coffee, admiring the noble peasants and making sagelike comments such as ‘There’s not much sign of stress around here, Aseem.’

The first half of the book sees them take it in turns to crowbar in all the LCHF articles of faith: physical activity won’t help you lose weight, saturated fat is good for you, cholesterol is nothing to worry about, sugar is a poison, a calorie is not a calorie, etc. I have neither the time nor inclination to fact-check all of their claims so I will allow for the possibility that they might be right from time to time. I am quite prepared to believe that the dangers of saturated fat have been overstated; better qualified people than Malhotra and O’Neill have been critical of the evidence for years. But whenever they touch on a topic with which I am familiar, I noticed that their discussion of evidence was partial and one-sided, and sometimes totally incorrect. On the occasions when I felt moved to follow up their (rather patchy) references, I nearly always found that there was less to them than meets the eye.

For example, Malhotra cites the PREDIMED study, a well-regarded piece of research which appeared to show significant benefits from the consumption of nuts and olive oil. But it did not, as Malhotra claims, show the superiority of a high-fat diet over a low-fat diet; such a hypothesis was never raised nor tested. He also cites the Lyon Diet Heart Study as evidence that ‘the standard American Heart Association recommended “low-fat diet”‘ causes more heart attacks than the Mediterranean Diet. The study does indeed show benefits from the Mediterranean Diet, but it is only by reading the study that you would see that the Mediterranean Diet was lower in both total fats and saturated fats than the ‘standard’ diet.

Some of the errors in the book are risible, such as when they claim that in ‘industrialised countries between 5 and 10 per cent of GDP is spent treating dental disease’ (the entire NHS budget takes up 9 per cent of GDP). Others are just sloppy, such as when they use a graphic from a newspaper to prove that poor diets cause 35 per cent of deaths (they don’t). Nearly all of them are consistent with a systematic bias towards a desired conclusion.

The reader should not have to look up the references in a book to find out what is being concealed. The nutritional epidemiology literature is enormous. Thousands of studies have been conducted and they do not all agree with one another. If one ignores the totality of the evidence and cherry-picks a handful of studies, it is possible to argue almost anything. If the reader cannot trust the author to play with a straight bat, he might as well save his money and go on a Google binge.

Take the chapter on sugar, for instance. The scientific consensus says that obesity is a risk factor for diabetes. Insofar as there is a link between sugar and diabetes, it is the same as the link between cheese and diabetes, ie. if you eat to much of it, you will become obese and therefore be at greater risk of diabetes. It is indirect.

A handful of dissenters claim that there is a direct link and that sugar can cause diabetes even in the absence of obesity. The most famous of them is Robert Lustig, a Californian endocrinologist who has views on sugar that are extreme by any standard. He has made various wild claims about sugar being ‘toxic’ and ‘addictive’. He calls it ‘the alcohol of the child’. Amongst other strange assertions, he has said that breast milk is not sweet and that pasta was invented in America. His published research on sugar is, in my view, third rate and I don’t think anybody should take him too seriously. But he is on the low carb bandwagon and is one of Malhotra’s chums. Consequently, while the chapter on sugar only references five studies, four of them are by Lustig and his colleagues, although this is not obvious from the text.

Even if the scientific consensus is wrong and Lustig turns out to be a sort of Galileo, shouldn’t Malhotra at least acknowledge the totality of the evidence, even if only to argue against it? And if there is an independent association between sugar and diabetes, why do organisations that want people to eat less sugar – such as SACN and Diabetes UK – continue to deny it? Is everybody in the pay of Big Sugar?

Malhotra’s credentials as a cardiologist are not sufficient to persuade me to ignore so many scientists. He says himself that ‘the majority of doctors are not equipped with even basic training to give specific, evidence-based lifestyle advice’ and admits that he doesn’t recall receiving ‘a single lecture at medical school on the impact of nutrition and lifestyle on preventing and treating disease’. All of his conclusions, he says, are based on ‘my own research’. But there are experts in this field who have received ample training and have been given many lectures on nutrition. They are called dieticians, and I have yet to meet one who endorses Malhotra’s message.

It soon becomes clear that The Pioppi Diet is not a serious review of the evidence. It provides a distorted and superficial account of a tiny fraction of the evidence. It does not really attempt to overturn the scientific consensus, it simply ignores it. Meanwhile, it devotes page after page to a handful of low carb activists who are portrayed as world-leading authorities, such as Zoe Harcombe, Tim Noakes, Nina Teicholz, Jason Fung and Robert Lustig. While all these people have books to sell, Malhotra and O’Neill accuse ‘many scientists and doctors’, as well as the media, of being ‘under the financial influence of the food and pharmaceutical industry’. This, we are told, is why they ‘disseminate selected, biased and outdated information’. When your best evidence is a single study from 1956 which has never been replicated, this is a bit rich.

So what is this Pioppi Diet that promises a ‘life-changing journey taking just 21 days’? The first thing to understand is that it is not a diet, it is a lifestyle. From wandering around Pioppi, Malhotra and O’Neill come to the profound conclusion that it is important to socialise with friends, take plenty of exercise, be relaxed and get some sleep. They can’t help you with socialising or stress relief, but they suggest you get at least seven hours sleep (which is also what the National Sleep Foundation recommends). With regards to exercise, O’Neill spends several pages waxing lyrical about high intensity interval training, but is forced to admit that they don’t do that kind of thing in Pioppi and so recommends getting up from your desk every 45 minutes to stretch your legs.

So much for the lifestyle. What about the food? Malhotra and O’Neill recommend that you avoid desserts, all sugars (including fruit juice and honey) and many of the most common sources of calories, including bread, rice, pasta, cereals, potatoes, noodles, couscous and ‘anything flour based’. You should also fast for 24 hours once a week and think about skipping breakfast every day (because the authors were told that Pioppi people used to be so poor that they sometimes went to work hungry). If you do all this, plus lots of walking and go to the gym five times a week (as Malhotra does) or engage in regular high intensity training (as O’Neill does), they reckon you will lose weight. And do you know what? I think they might be right. Behold the miracle of the Pioppi Diet!

The trouble with this whole concept is that Malhotra and O’Neill’s interpretation of the Pioppi Diet does not reflect what the people of Pioppi eat. It is basically an ultra-low carb version of the Mediterranean Diet with a few trendy ingredients, such as coconut oil, thrown in. Coconuts have never been part of the Italian diet and nor have ‘full-fat fermented dairy products’ but the authors include the latter anyway because – as they say – ‘the Greek cohort in Ancel Keys’s original studies enjoyed [them] … so there is no reason we shouldn’t be doing likewise!’

Do you know what the people of Pioppi actually eat? Processed carbohydrates. Farm workers in rural Italy do not – could not – survive on a diet of fish and seasonal vegetables. Pasta is as central to the Italian diet as potatoes are to Britain’s. So too is bread. This is the elephant in the room for anyone trying to pretend that Italians eat a low carb diet. As a 94 year old Pioppi resident said last year: ‘Pasta is my favourite food. I don’t understand why so many people try to cut that and bread out of their diets – it is like medicine for the heart and it is silly not to eat it.’

Once you accept that pasta and bread are important elements of Mediterranean cuisine, the actual Pioppi diet involves lots of fruit, vegetables, fish, starchy carbohydrates, mushrooms, nuts and eggs, but little or no cake, biscuits, processed meat, crisps and red meat. In other words, it is the UK government’s Eatwell Guide with extra virgin olive oil. Maybe those official dietary guidelines are not so deadly after all?

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