Sunday 23 November 2014

The man who tried to warn us about sugar

A British professor's 1972 book about the dangers of sugar is now seen as prophetic. Then why did it lead to the end of his career? Julia Llewellyn Smith tells the bittersweet story of John Yudkin

John Yudkin: an early critic of sugar
John Yudkin: an early critic of sugar

A couple of years ago, an out-of-print book published in 1972 by a long-dead British professor suddenly became a collector's item. Copies that had been lying dusty on bookshelves were selling for hundreds of pounds, while copies were also being pirated online.

Alongside such rarities as Madonna's Sex, Stephen King's Rage (written as Richard Bachman) and Promise Me Tomorrow by Nora Roberts; Pure, White and Deadly by John Yudkin, a book widely derided at the time of publication, was listed as one of the most coveted out-of-print works in the world.

How exactly did a long-forgotten book suddenly become so prized? The cause was a ground-breaking lecture called Sugar: the Bitter Truth by Robert Lustig, professor of paediatric endocrinology at the University of California, in which Lustig hailed Yudkin's work as "prophetic".

"Without even knowing it, I was a Yudkin acolyte," says Lustig, who tracked down the book after a tip from a colleague via an interlibrary loan. "Everything this man said in 1972 was the God's honest truth and if you want to read a true prophecy you find this book ... I'm telling you every single thing this guy said has come to pass. I'm in awe."

Posted on YouTube in 2009, Lustig's 90-minute talk has received 4.1 million hits and is credited with kick-starting the anti-sugar movement, a campaign that calls for sugar to be treated as a toxin, like alcohol and tobacco, and for sugar-laden foods to be taxed, labelled with health warnings and banned for anyone under 18.

Lustig is one of a growing number of scientists who don't just believe sugar makes you fat and rots teeth. They're convinced it's the cause of several chronic and very common illnesses, including heart disease, cancer, Alzheimer's and diabetes. It's also addictive, since it interferes with our appetites and creates an irresistible urge to eat.

This year, Lustig's message has gone mainstream; many of the New Year diet books focused not on fat or carbohydrates, but on cutting out sugar and the everyday foods (soups, fruit juices, bread) that contain high levels of sucrose. The anti-sugar camp is not celebrating yet, however. They know what happened to Yudkin and what a ruthless and unscrupulous adversary the sugar industry proved to be.

The tale begins in the Sixties. That decade, nutritionists in university laboratories all over America and Western Europe were scrabbling to work out the reasons for an alarming rise in heart disease levels. By 1970, there were 520 deaths per 100,000 per year in England and Wales caused by coronary heart disease and 700 per 100,000 in America. After a while, a consensus emerged: the culprit was the high level of fat in our diets.

One scientist in particular grabbed the headlines: a nutritionist from the University of Minnesota called Ancel Keys. Keys, famous for inventing the K-ration – 12,000 calories packed in a little box for use by troops during the Second World War - declared fat to be public enemy number one and recommended that anyone who was worried about heart disease should switch to a low-fat "Mediterranean" diet.

Instead of treating the findings as a threat, the food industry spied an opportunity. Market research showed there was a great deal of public enthusiasm for "healthy" products and low-fat foods would prove incredibly popular. By the start of the Seventies, supermarket shelves were awash with low-fat yogurts, spreads, and even desserts and biscuits.

But, amid this new craze, one voice stood out in opposition. John Yudkin, founder of the nutrition department at the University of London's Queen Elizabeth College, had been doing his own experiments and, instead of laying the blame at the door of fat, he claimed there was a much clearer correlation between the rise in heart disease and a rise in the consumption of sugar. Rodents, chickens, rabbits, pigs and students fed sugar and carbohydrates, he said, invariably showed raised blood levels of triglycerides (a technical term for fat), which was then, as now, considered a risk factor for heart disease. Sugar also raised insulin levels, linking it directly to type 2 diabetes.

When he outlined these results in Pure, White and Deadly, in 1972, he questioned whether there was any causal link at all between fat and heart disease. This was not what the food industry wanted to hear. When devising their low-fat products, manufacturers had needed a fat substitute to stop the food tasting like cardboard, and they had plumped for sugar. The new "healthy" foods were low-fat but had sugar by the spoonful and Yudkin's findings threatened to disrupt a very profitable business.

As a result, says Lustig, there was a concerted campaign by the food industry and several scientists to discredit Yudkin's work. The most vocal critic was Ancel Keys.

Keys loathed Yudkin and, even before Pure, White and Deadly appeared, he published an article, describing Yudkin's evidence as "flimsy indeed".

Yudkin was "uninvited" to international conferences. Others he organised were cancelled at the last minute, after pressure from sponsors, including, on one occasion, Coca-Cola. When he did contribute, papers he gave attacking sugar were omitted from publications. The British Nutrition Foundation, one of whose sponsors was Tate & Lyle, never invited anyone from Yudkin's internationally acclaimed department to sit on its committees. Even Queen Elizabeth College reneged on a promise to allow the professor to use its research facilities when he retired in 1970 (to write Pure, White and Deadly). Only after a letter from Yudkin's solicitor was he offered a small room in a separate building.

"Can you wonder that one sometimes becomes quite despondent about whether it is worthwhile trying to do scientific research in matters of health?" he wrote. "The results may be of great importance in helping people to avoid disease, but you then find they are being misled by propaganda designed to support commercial interests."

And this "propaganda" didn't just affect Yudkin. By the end of the Seventies, he had been so discredited that few scientists dared publish anything negative about sugar for fear of being similarly attacked. As a result, the low-fat industry, with its products laden with sugar, boomed.

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