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

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.