All Diet Books Do NOT Lie — An Open Letter to Vox Editor Ezra Klein
On March 24, Julia Belluz wrote a hostile review of my new book Always Hungry? for the online news site Vox titled: Diet Books Are Full of Lies. But They’re Even Worse When Doctors Write Them. I complained to the editor of Vox, Ezra Klein, that the article was fundamentally inaccurate, unfair and unprofessional. To his credit, Klein agreed to investigate and on April 27 published a substantially revised version that deleted the egregious title. The revision toned down the personal attack and included a few comments I provided by email (in an edited and highly abridged form). However, the revision remains unbalanced, and Vox refused to publish my full response. Furthermore, the original article was published with much fanfare — its inflammatory title attracting widespread attention (e.g., 15k Facebook shares). For that reason, I’m posting my response to the original article as an open Letter to the Editor. (The original and revised versions of the article are available for comparison here and here).
Dear Mr. Klein:
In her March 24, 2016 article about my book, Vox staff reporter Julia Belluz accused me of lying. Such an accusation should never be made casually, and the target of that sort of attack should be given a chance to respond. I was not given that opportunity. In fact, virtually everything I said in an extensive interview with Belluz was disregarded, as were major aspects of the book that would have undermined her distortions of my work. The article failed even to inform your readers that she had interviewed me at length.
Belluz’s argument is largely premised on factual error. As explicitly stated in Always Hungry?, the pilot test with which she finds fault was never intended as scientific proof of the long-term effectiveness of my book’s program. The higher-fat diet I recommend is based on dozens of studies from my research team and hundreds of studies by others. No diet ever recommended (including by the government) has been proven by a definitive randomized controlled trial. So the relevant question isn’t whether there’s proof, but rather how the evidence for alternative approaches compares to conventional recommendations.
For 40 years, the public has been told that the best way to lose weight is to cut back on calories and fat. But this advice has failed miserably in practice and disregards that body weight is controlled more by biology than will power over the long term. With calorie deprivation, hunger increases and metabolism slows — a recipe for weight regain. I wrote Always Hungry? to provide an alternative approach focused on the biological drivers of weight gain, supported by hundreds of scientific references. Is it fair to demand that new approaches be subject to far higher standards of evidence than has ever applied to existing recommendations? Or does Belluz reserve her attacks only for books that challenge conventional thinking?
Systematic reviews consistently report LESS weight loss on conventional low-fat diets compared to all higher-fat diets, low-carbohydrate diets, very-low-carbohydrate diets, or Mediterranean diets. High fat and calorie dense foods like nuts, olive oil and dark chocolate are not associated with weight gain in the best observational research, whereas processed carbohydrates top the list. Of particular interest, the Look Ahead study was terminated prematurely for “futility” when its low-fat diet showed no promise of ever reducing cardiovascular disease. Compare that result to Predimed, a study that also closed early, but in this case because the higher-fat diets demonstrated unexpectedly great protection again cardiovascular disease. These important new findings notwithstanding, the majority of the US public remains focused on reducing dietary fat according to a Gallup poll, having been taught to fear fat by the government, professional nutritional organizations and the food industry. Some experts even recommended sugar in the 1990s as a good way to “dilute” calories from dietary fat.
Belluz also takes issue with the title of my book but fails to note that many weight loss publications by professional societies and the government refer to potential benefits in the title. Consider for example, American Heart Association No-Fad Diet: A Personal Plan for Healthy Weight Loss. That title doesn’t make clear that not everyone will lose weight or that the weight loss might be temporary. Further, no long-term trial proved that calorie restriction, their recommended approach, was healthy or, more importantly, effective. That’s why it’s crucial to consider the contents of any diet book, especially those that make sensational weight loss claims (mine doesn’t).
Finally, Belluz faults me for featuring anecdotal stories of participants of the pilot test. But anecdotes have a long history in medicine and journalism as a way to convey personal experience. (For a March 26 tie-in article, Belluz herself asked readers to send in their experiences following popular diets.) I included these stories not only to share success, but also to highlight challenges and how they might be conquered — a critical but not easily quantifiable aspect of lifestyle change. Furthermore, individuals featured in the book reflect a range of responses that can occur in weight loss programs, including those who had lost more than 2 pounds a week and those who lost less than ½ pound a week. And unlike some popular diet books, all personal stories were real and provided without financial compensation.
With preliminary evidence that obesity has begun to shorten life-expectancy in the US, it’s critically important that we consider alternative approaches to weight control and chronic disease prevention. Journalists have a vital role to play in this regard by raising public awareness and fostering a vigorous scientific debate. Unfortunately, articles like Belluz’s blur the boundary between legitimate journalism and polemics, offering a vehicle for others to advance a personal agenda through blogs and social media, to the detriment of responsible and respectful dialogue.