Sugar
The substance we slowly figured out was a problem
Description
In 1972, a British nutrition researcher named John Yudkin published a book called Pure, White and Deadly. The argument was direct: sugar consumption, not saturated fat, was the leading dietary contributor to cardiovascular disease, type 2 diabetes, and obesity. Yudkin had spent two decades at Queen Elizabeth College in London running studies on carbohydrate metabolism, and his data had pointed him in a direction that put him at odds with the dominant figure in nutrition science, the American physiologist Ancel Keys, who insisted the culprit was saturated fat. The two men did not get along. Yudkin lost the argument professionally and personally. His funding dried up, his book was dismissed, and his career ended in something close to disgrace.
Yudkin died in 1995. Pure, White and Deadly was reissued in 2012 with a foreword by the British endocrinologist Robert Lustig, who had spent the previous decade arguing that fructose, the sweet half of table sugar, behaved metabolically more like a slow toxin than a calorie. By the time of the reissue, the diabetes-obesity epidemic had become impossible to dismiss as a fat-driven phenomenon — fat consumption had remained roughly stable while sugar consumption had risen, and the metabolic conditions had risen with the sugar. The story Yudkin had been trying to tell was being rediscovered.
Then, in 2016, a paper in JAMA Internal Medicine made the dispute look more deliberate than scientific. Researchers at the University of California, San Francisco had found internal documents from the Sugar Research Foundation showing that, in 1967, the trade group had paid Harvard scientists to publish a literature review in the New England Journal of Medicine that minimized the role of sugar in heart disease and emphasized fat. The names of the funders had not been disclosed. The reframing of cardiovascular nutrition that followed had been shaped, at least in part, by industry-funded research designed to point attention elsewhere.
The question we're asking: how did sugar move from dietary background to recognized metabolic problem, and how long did it take?
What we'll see: Yudkin's dismissal, the industry's role, the fructose research, and what current guidance now says.
Table of contents
01Pure, White and Deadly
John Yudkin was the founding professor of nutrition at Queen Elizabeth College and one of the small number of scientists in the 1950s and 1960s running careful metabolic studies of carbohydrate intake. His method was unfashionable in the period when nutritional epidemiology was producing the country-level correlations that drove the saturated-fat consensus. Yudkin preferred controlled feeding studies — putting volunteers on defined diets and measuring how their lipids, glucose, and insulin changed. His data suggested that sucrose consumption raised triglycerides and impaired glucose tolerance in ways that fat consumption did not.
Pure, White and Deadly laid out the argument for general audiences. Yudkin pointed at the rise of sugar consumption in industrialized countries — from a few pounds per person per year in the eighteenth century to over a hundred pounds per person per year by the mid-twentieth — and at the parallel rise of cardiovascular disease, diabetes, and obesity. The correlation was stronger than the saturated-fat correlation, and it had a metabolic mechanism: sucrose is half fructose, fructose is metabolized differently from glucose, and the metabolic byproducts looked like trouble.
02The 2016 disclosure
The September 2016 JAMA Internal Medicine paper, by Cristin Kearns, Laura Schmidt, and Stanton Glantz at UCSF, examined internal correspondence from the Sugar Research Foundation, the predecessor of today's Sugar Association. The documents showed that in 1965, the foundation had paid two Harvard nutrition researchers — Mark Hegsted and Frederick Stare — around fifty thousand dollars in current value to write a literature review on dietary causes of coronary heart disease.
The review appeared in two parts in the New England Journal of Medicine in 1967. It concluded that the available evidence pointed to dietary fat and cholesterol as the primary cardiovascular concerns, while finding the case against sucrose unconvincing. The funding source was not disclosed. The methodological choices the authors made — which studies they emphasized, which they treated as flawed — were consistent with the brief the foundation had set. Hegsted later became the head of nutrition at the US Department of Agriculture and was a principal author of the 1977 dietary guidelines that formalized the saturated-fat consensus.
03Fructose and the liver
The metabolic case against sugar that emerged in the 2000s focused on fructose. Glucose, the other half of sucrose, is metabolized by every cell and tightly regulated by insulin. Fructose is metabolized almost entirely in the liver. When fructose intake is modest, as from fruit, the liver handles it without obvious harm. When intake is large and chronic, as it became with high-fructose corn syrup and the sweetening of beverages, the liver shifts toward de novo lipogenesis, converting fructose into fat. The pattern looks remarkably similar to what alcohol does to the liver.
The clinical consequence has been the rise of non-alcoholic fatty liver disease, or NAFLD, the most common chronic liver condition in the developed world. NAFLD now affects roughly 25-30% of adults globally, closer to 40% in the US. A subset progresses to inflammation and fibrosis, a smaller subset to cirrhosis. The condition was unusual enough in 1980 that the term had not been coined. By 2020 it was the leading reason for liver transplant referrals in non-alcoholic patients. Fructose was the most plausible driver.
04Where guidance ended up
By the late 2010s, formal dietary guidance had updated. The 2015 World Health Organization recommendation set a target of limiting added sugar to under 10% of daily caloric intake, with a conditional recommendation of under 5%. The 2015-2020 US Dietary Guidelines for the first time set an explicit limit on added sugars. Mexico imposed a sweetened-beverage tax in 2014, the UK in 2018, both with measurable reductions in consumption. The institutional position had shifted from sugar as background calories to sugar as a specific dietary risk factor.
The food industry response has been familiar. Reformulation has reduced added sugar in some product categories. Marketing of low-sugar variants has increased. But added sugars remain ubiquitous in processed foods, including products not commonly thought of as sweet — bread, condiments, soups, salad dressings. The portion of American caloric intake from added sugars peaked in the early 2000s and has declined modestly, but it remains higher than the WHO recommendation for most of the population. The pattern matches what happened with sodium and trans fats: institutional acknowledgment of the problem, industry resistance to mandatory limits, slow voluntary reformulation.
05Conclusion
John Yudkin was right about more than he was wrong about, and he died before the field acknowledged it. The institutional dismissal of his hypothesis in the 1970s, partly driven by industry-funded counter-research, set back the clinical understanding of carbohydrate metabolism by a generation. The fructose biology, the NAFLD epidemic, and the sweetened-beverage taxes all rest on a foundation Yudkin laid and was punished for laying.