"There is no such thing as a miracle diet, but if there's a miracle meeting, this is it." That was how Fiona Godlee, editor-in-chief of The BMJ, introduced the "Food for Thought" conference. The event, co-sponsored by The BMJ and global reinsurer SwissRe, took place last week in Zurich, Switzerland.
The "miracle" Godlee referred to was that, for the first time, speakers with genuinely different viewpoints engaged in discussion on some of nutrition science’s most controversial issues, including the health claims made around saturated fats and low-carbohydrate diets.
"One big reversal [in our thinking] is the demonization of fat,” Godlee said in wrapping up. “I think we've got to recognize those reversals, acknowledge them, and have some humility about what is said....And I think that the humility must extend to guidelines." She called for science-based evidence that is "transparent, reproducible, and independent" to adequately address the global nutrition crisis. Watch her remarks here.
Godlee emphasized the importance of such a conference, given the tremendous urgency surrounding the continued, crisis-level epidemics of obesity and type 2 diabetes. She asserted that there are few areas of health "more important" and "more neglected in medical education" than nutrition. 1
Conference participants included some of the most influential architects of current nutrition policy—such as Walter Willett, Professor of Epidemiology and Nutrition at the Harvard T.H. Chan School of Public Health; Dariush Mozaffarian, Dean of the Friedman School of Nutrition Science and Policy at Tufts; Michael Lean, Chair of Human Nutrition at University of Glasgow; and Nita Farouhi, Professor of Population Health and Nutrition at University of Cambridge—as well as critics of that policy, including researcher Zoe Harcombe, author and journalist Gary Taubes, and executive director of The Nutrition Coalition (TNC) Nina Teicholz.
The panel on low-carbohydrate diets was especially lively, with different views expressed about the causes of and cures for obesity and type 2 diabetes. Most of the panelists believed that caloric excess caused these diseases and that any type of diet worked to reverse them, so long as it resulted in weight loss. Indeed, extreme caloric restriction has been demonstrated to reverse diabetes and was presented by study co-author and panelist member Roy Taylor from Newcastle University.
Sarah Hallberg, medical director of the obesity clinic at Indiana University Health and chair of TNC's scientific council, made the point that diabetes can be reversed in two additional ways: bariatric surgery and carbohydrate restriction. She presented data from her own large trial showing 60% reversal of diabetes after one year on a low-carbohydrate diet.
An emerging consensus was that diabetes could be considered reversible and not a progressive, lifelong chronic condition. As Godlee said in her closing comments, "I think there may be a tipping point that we're hearing about the reversal of some conditions, diabetes and obesity being two [of them]."
Another conference highlight was a series of discussions over whether evidence from nutritional epidemiology can reliably be used to inform nutrition policy. This topic is crucially important, as most of America's dietary guidelines are currently based on this type of evidence.
Stanford University Professor John Ioannidis, a prominent critic of the field, gave an hour-long talk via video link that described the weak nature of epidemiological data, the high potential for confounding, and the stark record of nutritional epidemiological findings failing to be confirmed by clinical trials (a more rigorous kind of evidence).
Willett, who has directed the country's most prominent epidemiological study for most of his career, sat in the front row during the talk and contested several points. Mozaffarian, who has also has published many papers based on epidemiology, devoted his closing comments the next day to a 10-minute rebuttal of Ioannidis.
On a panel devoted to food politics and policy, Martin White from the University of Cambridge addressed the problem of the food industry's influence on nutrition science and policy, while Sonia Angell from New York City's Department of Public Health talked about her department's policies to reduce salt and trans fats.
TNC's Nina Teicholz spoke about the data suggesting that the American public had, actually, followed the country’s dietary guidelines over recent decades and that the failure of these guidelines to promote good health must spur questions about the soundness of their scientific basis.
Where strong evidence is lacking, it would be better for governments to "remain silent," Teicholz urged, a point echoed by Godlee in her closing remarks.
Other challenges to the guidelines came from Salim Yusuf, of McMaster's University, who presented a substantial body of evidence contrary to the "lower is better" recommendation on salt. Together with Mozaffarian during the final remarks, they also agreed that there was insufficient evidence to continue with caps on saturated fats. Godlee called this an "emerging consensus" and said,: “Maybe one outcome of this meeting would be for this meeting to say ‘that’s gone now’, the science [on saturated fats] has changed....t seems to be that should be an outcome of some sort from this meeting… [yet] there doesn’t seem to have been an enormous ‘mea culpa’ from the scientific community that we got it so wrong. That does surprise me.”
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[Updated July 13 with more complete quote from Fiona Godlee]