If you’re interested in diet, I recommend Stephan Guyenet’s review of Gary Taubes new book:
The Case Against Sugar is a journey through sugar history and science that argues the point that sugar is the principal cause of obesity, diabetes, coronary heart disease, and many other common noncommunicable diseases. This differs from the prevailing view in the research and public health communities that obesity and noncommunicable disease are multi-factorial, with refined sugar playing a role among other things like excess calorie intake, physical inactivity, cigarette smoking, alcohol and illegal drug use, and various other diet and lifestyle factors. I side with the latter view.
Some key quotes:
Taubes argues that sugar is the only factor that reliably shows up when a culture develops Western noncommunicable diseases, supporting the point with examples of cultures that adopted sugar-rich diets and became ill. Yet he makes no effort to look for a counterexample that could refute his argument: a traditionally-living culture that has a high intake of sugar and does not suffer from Western noncommunicable diseases. If such a culture can be found, this piece of evidence is sufficient to reject Taubes’s argument that sugar reliably associates with the onset of these diseases in a population. Let’s do Taubes’s research for him. A well-studied Tanzanian hunter-gatherer tribe called the Hadza gets 15 percent of its average year-round calorie intake from honey, plus fruit sugar on top of it. This approximates US sugar intake, yet the Hadza do not exhibit obesity, cardiovascular disease, or any of the other disorders Taubes attributes to sugar. In fact, many hunter-gatherer groups relied heavily on honey historically, including the Mbuti of the Congo whose diet was up to 80 percent honey during the rainy season. Yet they do not exhibit obesity or insulin resistance.
Taubes upbraids the research community for its belief that body fatness is determined by calorie intake, rather than the impact of foods on insulin. He supports the latter proposition with semi-anecdotal observations from Africa suggesting that a group of people eating a high-sugar diet supplying “as little as sixteen hundred calories per day” were sometimes obese and diabetic. A person who actually wants to get to the bottom of this question should conduct their investigation in a very different manner. The first order of business is to look up the relevant metabolic ward studies, which are the most tightly controlled diet studies available. These studies consistently show that calorie content is the only known food property that has a meaningful impact on body fatness. This is true across a wide range of carbohydrate-to-fat ratios and sugar intakes, and a correspondingly wide range of insulin levels. What makes Taubes’s oversight so extraordinary is that he was involved in funding one of these metabolic ward studies, which compared two diets that differed tenfold in sugar content. The results showed that a 25 percent sugar, high-carbohydrate diet caused slightly more body fat loss than a 2.5 percent, very-low-carbohydrate (ketogenic) diet of equal calories (18). Despite these clear and consistent findings, Taubes continues to insist that calorie intake is not an important determinant of body fatness, and he offers the reader questionable evidence in support of this while omitting high-quality evidence to the contrary. All while exuding righteous indignation about the scientific community’s misguided beliefs.
His discussion of the history of research on sugar, fat, and obesity is less compelling due to its one-sided nature. For example, The Case Against Sugar portrays an epic struggle decades ago between researchers who believed that saturated fat was the primary cause of coronary heart disease, and those who believed that sugar was. These views are embodied by the American researcher Ancel Keys and the British researcher John Yudkin, respectively. Taubes makes hay of the fact that Keys was supported in part by the sugar industry, painting Yudkin as a righteous underdog standing up to a corrupt and aggressive Keys. Yet he never gives serious consideration to the strength of the evidence supporting each man’s beliefs, instead using a historical narrative to imply that Keys was a stooge of the sugar industry who unfairly won the argument due to his sharp elbows (whether or not this is true, it’s also true that Yudkin’s evidence was not as compelling as Keys’s). This tactic of using historical narratives as a substitute for evidence is one that recurs throughout the book. In his haste to undermine Keys, Taubes neglects to mention that Yudkin had his own conflicts of interest: he was funded by the egg, edible oil, and dairy industries, all of which had an interest in pinning the blame for obesity and chronic disease on sugar
(I made the same point as that last one here.)
I’m recommending this review more strongly than usual because I’ve previously praised Taubes. He did a good job explaining how the pop wisdom of the ’90s – that fat was uniquely bad – wasn’t true. He did a good job showing the ways in which the old “just diet and exercise, nothing can go wrong” idea was simplistic and needed to be replaced with a good understanding of obesity set points. I learned some useful things from his books and I had positive feelings about him.
But from the first time I talked about him almost five years ago, I’ve stressed that his views about sugar are really, really wrong. I was previously willing to excuse this on the grounds that he wrote about a lot of other useful things and everybody’s allowed a bit of crazy speculation once in a while before a field is completely settled. But at this point things seem pretty settled and I no longer think his behavior is excusable. The ’90s are over, the pop wisdom that Taubes set out to debunk is sufficiently debunked, and he’s doubling down on his sugar theory despite an increasing pile of evidence against it.
I apologize if my past praise for Taubes’ writing have helped create a climate where people listen to his theories. His good qualities aren’t enough to justify the increasing amount of misinformation he’s putting out, and I don’t recommend him on any level as a source of nutritional advice.