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Putting Nutrition Claims to the Test

Gary Taubes has been the most influential voice in nutrition since Ancel Keys, but since Keys is now universally excoriated, that may not be an unmitigated honor: how do we know that Taubes is not as flawed? It is certainly unprecedented for the most influential voice of a major scientific discipline, in this case nutrition, to be a journalist rather than a scientist, but since Keys was a scientist, perhaps nutrition does need to be led by a non-scientist. Let’s see.

Between 1953 and 2002, the world of nutrition was dominated by Ancel Keys’s hypothesis that heart attacks and strokes were caused by an excess of fat in the diet,[1] but in 2002 Taubes wrote an article in the New York Times Magazine “What if It’s All Been a Big Fat Lie?” that almost overnight converted the nutritional avant garde from fat-phobia to carbohydrate-phobia.[2] Taubes went on to expand his article into the best-selling 2007 book Good Calories, Bad Calories.[3]

Taubes, a physicist who became a science journalist, has made a career of exposing poor research. To expose the brutal politics within the world of high-energy physics, he subtitled his first book Nobel Dreams (1986) as Power, Deceit and the Ultimate Experiment. In 1993 he published his second book, Bad Science: The Short Life and Weird Times of Cold Fusion, to analyze the failings of the Fleischmann-Pons experiment. Having eviscerated physics, Taubes moved on to nutrition because, in his words, “I had a lot of people in the physics community say to me that if I was interested in bad science I should look at this stuff in public health because that is really bad.”[4]

So, what is Taubes’s difficulty with the Keys fat hypothesis? Keys (1904–2004) of the University of Minnesota faced the problem, as did all of America in the 1950s, of the sudden epidemic of heart attacks. Frighteningly, these had seemingly come out of nowhere. Absence of evidence is not evidence of absence, but in a study published in the British Heart Journal Leon Michaels, a Canadian physician, showed that the absence of evidence for heart attacks before the 20th century was indeed evidence for their absence.[5] Cleverly, Michaels compared the characteristic chest pain of heart attacks with the characteristic pain and symptoms of migraine and gout, showing that whereas frequent descriptions of migraine and gout can be found in medical texts from all eras, stretching back to Greek and Roman times, angina and heart attacks started to be described with any frequency only in the 20th century: heart attacks really were a new disease, yet a plague of them had descended on the United States like avenging angels, and by midcentury they had become by far the commonest cause of death. Nor were they respecters of persons: President Eisenhower had a heart attack in 1955, while Franklin Roosevelt had died from the related condition of stroke.

Heart attacks and strokes are caused by atherosclerosis, which used to be known as “hardening” of the arteries but which is better described as “inflammation” of the arteries. By Keys’s day it seemed clear that atherosclerosis, in its turn, was caused by the deposition of cholesterol in the arteries, and since people with heart attacks had raised levels of cholesterol in the blood, and since eating an excessive amount of saturated fat raised the blood levels of cholesterol, it seemed obvious that cutting back on fat in the diet would help prevent heart attacks and their related condition of strokes.

And it did! Contrary to myth – a myth to which Taubes himself has contributed – the course of the heart attack epidemic in America followed the Keys fat paradigm almost faultlessly. So between 1960 and 2000 the per capita U.S. consumption of

  • saturated fatty acids fell from 55 to 46 grams per day
  • cholesterol fell from 465 to 410 milligrams per day.

Meanwhile the per capita U.S. consumption of

  • carbohydrates rose from 380 to 510 grams per day
  • fiber rose from 18 to 26 grams per day.[6]

And at the same time, the incidences of heart attacks and strokes in America … collapsed! So between 1970 and 2010 the heart attack rate fell by 75 per cent (i.e., in 2010 it was only a quarter of the rate in 1970) while the stroke rate fell markedly too.[7] Has Keys not been exonerated and Taubes disproved by these data? And with that extraordinary public benefit, need we worry about a bit of diabetes and a touch of obesity? These are, after all, apparently translating into a remission of the epidemic of heart disease.

I am of course writing that penultimate sentence ironically. The facts are unambiguous, but the truth – as Taubes himself acknowledges – is that we still don’t know what has caused the remission in heart disease nor the current epidemics in obesity and type 2 diabetes. Taubes blames the latter on sucrose, but I think the case is not yet proven – and indeed neither does Taubes, hence his wonderful initiative in creating with Dr. Peter Attia the Nutrition Science Initiative (NuSI) to study health to the highest standards of scientific objectivity.

As his essay demonstrates, Gary Taubes deservedly remains the most influential person in nutrition today, not only because he smashed the fat consensus, and not only because he has recognized the metabolic syndrome as the greatest health threat facing the western world today, but also because he is honest enough to know that even his own faith in the sugar hypothesis needs dispassionate testing. Moreover, in his defense of science as a process that must be freed from government demands for immediate results, he has shown he understands the scientific method better than many a practicing nutritional researcher.

    

Notes


[1] A Keys (1953) Atherosclerosis: A problem in newer public health. Journal of the Mount Sinai Hospital 2: 118-139.

[2] G Taubes (7th July 2002) “What if It’s All Been a Big Fat Lie?” New York Times Magazine.

[3] G Taubes (2007) Good Calories, Bad Calories Knopf NY.

[4] Quoted by B Appleyard (1 January 2017) How sugar got us in a sticky mess. Sunday Times Magazine, p 24-27.

[5] L Michaels (1966) Aetiology of coronary heart disease: An historical approach. Br Heart J 28: 258-264.

[6] S-S Zhou et al (2010) B-vitamin consumption and the prevalence of diabetes and obesity among US adults: population based ecological study. BMC Public Health 10: 746. www.biomedcentral.com/1471-2458/10/746

[7] A Statement from the American Heart Association/American Stroke Association (2013) Factors Influencing the Decline in Stroke Mortality. https://professional.heart.org/idc/groups/ahamah-public/@wcm/@sop/@smd/documents/downloadable/ucm_458896.pdf p8. Accessed December 2016.

 

Also from This Issue

Lead Essay

  • Unintended Consequences, Special Interests, and Our Problem with Sugar by Gary Taubes

    Gary Taubes tells a tale of unintended consequences: When the U.S. Department of Agriculture issued the first federal dietary guidelines, it may have hoped to steer Americans away from excess fat and toward a diet of whole fruits and vegetables. But this did not happen: Overwhelmingly, Americans turned to processed, sugary, and high-carbohydrate foods instead. The result was an epidemic of obesity. Meanwhile, dietary science continued to evolve. The case against fat weakened significantly, while the case against sugar strengthened. Yet scientists do not deal in certainties; their findings come with varying degrees of confidence, a state of affairs that public policy has difficulty reflecting.

Response Essays

  • Americans Eat Too Much Cake, but the Government Isn’t To Blame by Stephan Guyenet

    Stephan Guyenet says Americans can’t blame government nutrition advice for their overconsumption of sugar. Dietary guidelines issued in 1980 didn’t recommend substituting sugars for fats; they recommended decreasing consumption of both. Americans, however, started eating more sugar anyway. Nor is it clear that sugar is to blame for obesity, because American sugar consumption peaked in 1999 and has declined ever since. Meanwhile, obesity has continued on a steady upward trend. Sugar is one part of a larger picture that explains American obesity, diabetes, and heart disease; it is not the sole culprit.

  • Unintended Consequences, Special Interests, Sugar, and a View from the Clinical Trenches by Yoni Freedhoff

    Yoni Freedhoff says that the public policy debate about nutrition would benefit from a practical, clinical perspective. American’s eating habits have changed a lot since 1977, and while sugar is a part of that change, it’s only one part among many. Americans eat more meals outside the home. They eat more pre-packaged ready-to-eat meals. They eat larger portions. And they eat many more calories altogether. The case against fat in the 1970s and 1980s was certainly flawed, but those flaws can’t be blamed for Americans’ poor dietary choices in the meantime, and, what’s worse, today’s critics of sugar may be replicating some of the same mistakes.

The Conversation