One teaspoon of sugar equates to 4 grams. The Harvard scientists and the sugar executives with whom they collaborated are no longer alive. One of the scientists who was paid by the sugar industry was D. Mark Hegsted, who went on to become head of nutrition at the US Department of Agriculture, where in 1977 he helped draft the forerunner to the federal government's dietary guidelines. Another scientist was Fredrick J. Stare, chairman of Harvard's nutrition department. In a statement responding to the JAMA report, the Sugar Association said the 1967 review was published at a time when medical journals did not typically require researchers to disclose funding sources or potential financial conflicts of interest. The New England Journal of Medicine did not begin to require financial disclosures until 1984. The industry "should have exercised greater transparency in all of its research activities," the Sugar Association statement said. Even so, it defended industry-funded research as playing an important and informative role in scientific debate. It said that several decades of research had concluded that sugar "does not have a unique role in heart disease." The association also questioned the motives behind the new paper.

"Most concerning is the growing use of headline-baiting articles to trump quality scientific research," the organisation said. "We're disappointed to see a journal of JAMA's stature being drawn into this trend." But even though the influence-peddling revealed in the documents dates back nearly 50 years, the revelations are important because the debate about the relative harms of sugar and saturated fat continues today, Glantz said. For many decades health authorities encouraged Americans to improve their health by reducing their fat intake, which led many people to consume low-fat, high-sugar foods that some experts now blame for fuelling the obesity crisis. "It was a very smart thing the sugar industry did because review papers, especially if you get them published in a very prominent journal, tend to shape the overall scientific discussion," he said. Hegsted used his research to influence the government's dietary recommendations, which emphasised saturated fat as a driver of heart disease while largely characterising sugar as empty calories linked to tooth decay. Today, the saturated fat warnings remain a cornerstone of the government's dietary guidelines, though in recent years the American Heart Association, the World Health Organization and other health authorities have also begun to warn that too much added sugar could increase cardiovascular disease risk. Marion Nestle, a professor of nutrition, food studies and public health at New York University, wrote an editorial accompanying the new paper that said the documents provided "compelling evidence" that the sugar industry initiated research "expressly to exonerate sugar as a major risk factor for coronary heart disease."

"I think it's appalling," she said. "You just never see examples that are this blatant. The amount of money they were paid to do this is staggering." Nestle noted that efforts by the food industry to shape nutrition science continue today. Last year, an article in The New York Times revealed that Coca-Cola, the world's largest producer of sugary beverages, had provided millions of dollars in funding to researchers who sought to downplay the link between sugary drinks and obesity. In June, The Associated Press reported that candy-makers were funding studies that claimed that children who eat candy tend to weigh less than those who do not. The JAMA paper relied on thousands of pages of correspondence and other documents that Cristin E. Kearns, a postdoctoral fellow at UCSF, discovered in archives at Harvard, the University of Illinois and other libraries. The documents show that in 1964, John Hickson, a top sugar industry executive, discussed a plan with others in the industry to shift public opinion "through our research and information and legislative programs."

At the time, studies had begun pointing to a relationship between high-sugar diets and the country's high rates of heart disease. At the same time, other scientists, including the prominent Minnesota physiologist Ancel Keys, were investigating a competing theory that it was saturated fat and dietary cholesterol that posed the biggest risk for heart disease. Hickson proposed countering the alarming findings on sugar with industry-funded research. "Then we can publish the data and refute our detractors," he wrote. In 1965, Hickson enlisted the Harvard researchers to write a review that would debunk the anti-sugar studies. He paid them a total of $6500 - the equivalent of $49,000 today. Hickson selected the papers for them to review and made it clear he wanted the result to favour sugar. Harvard's Hegsted reassured the sugar executives. "We are well aware of your particular interest," he wrote, "and will cover this as well as we can." As they worked on their review, the Harvard researchers shared and discussed early drafts with the sugar executive, who responded that he was pleased with what they were writing. The Harvard scientists had dismissed the data on sugar as weak and gave far more credence to the data implicating saturated fat.

"Let me assure you this is quite what we had in mind, and we look forward to its appearance in print," Hickson wrote. After the review was published, the debate about sugar and heart disease died down, while low-fat diets gained the endorsement of many health authorities, Glantz said. "By today's standards they behaved very badly," he said. New York Times