Gary Taubes Can't Accept He's Wrong About the Science of Obesity
In 2012, Gary Taubes, a journalist who has penned numerous popular books extolling the benefits of low-carbohydrate, high-fat diets to treat obesity, launched the Nutrition Science Initiative (NuSI), a laudable effort to fund rigorous scientific studies to research his key contention: that it's not the number of calories that counts when it comes to weight gain, but rather the type of calories. If the NuSI experiments backed his hypothesis, decades of conventional dietary wisdom would be overturned. Rather than telling the more than 100 million Americans who are obese to eat less and move more, we should take Taubes' advice and simply advocate eating far fewer carbohydrates.
So it was with great interest that I noticed Taubes' name in the byline of a piece published at STAT on September 13th. "How a ‘fatally, tragically flawed’ paradigm has derailed the science of obesity," the headline boldly proclaimed. Had Taubes' effort found the evidence it sought? Would nutrition textbooks need to be rewritten?
I eagerly devoured the article, and even linked it on RealClearScience, but overall, I was greatly disappointed. Taubes spent much of his 5,000+ words attacking the "energy balance notion" of weight gain (i.e. calories in, calories out), but where was the evidence supporting his alternative hypothesis that eating more fat and fewer carbohydrates is the way to go?
Alas, I found it, relegated to a parenthetic statement in the fourth to last paragraph:
Over the course of my research, I came to find the arguments of these diet books compelling, so much so that I’ve written four books myself on the subject and co-founded a not-for-profit organization in 2012, the Nutrition Science Initiative, to help fund research that might shed meaningful light on the causes of common obesity. (The results were encouraging but ambiguous.)
"Encouraging but ambiguous"? That doesn't sound too encouraging... So I checked NuSI's research. Taubes' description was euphemistic to say the least. Two of the three NuSI studies designed to test Taubes' fat metabolism hypothesis did not support the notion.
Here is NuSI's own description of the DIETFITS Trial:
Over a 2-year period, 609 participants in five cohorts were enrolled in the trial and were randomized to [a healthy low-fat or a health low-carbohydrate diet]. Participants were given no explicit instructions to reduce calorie intake, but were instructed to eat “healthy” diets, which, among other features, maximized vegetable intake, minimized intake of added sugars and refined flours, and focused on minimally processed foods that were prepared at home. The two groups prescribed the “healthy low-fat“or “healthy low-carbohydrate” diets showed significant differences in their carbohydrate and fat intakes. However, despite these differences, the low-carbohydrate and low-fat diet groups lost similar amounts of body weight during the trial.
The outcome of the Energy Balance Consortium Pilot Study was more damning. Subjects were fed a isocaloric low-carbohydrate diet while their energy expenditure was closely monitored. As the researchers concluded:
"We found that a carefully controlled isocaloric ketogenic diet (KD) coincided with small increases in energy expenditure (EE) that waned over time. Despite rapid, substantial, and persistent reductions in daily insulin secretion and RQ after introducing the KD, we observed a slowing of body fat loss. Therefore, our data do not support the carbohydrate–insulin model predictions of physiologically relevant increases in EE or greater body fat loss in response to an isocaloric KD."
So it seems that Taube's initiative actually refuted his hypothesis, yet here he is, nine years later, still trumpeting the same ideology! True to form, he actually published a new book pushing low-carb eating last winter.
As it turns out, there were actually significant struggles behind the scenes at NuSI. The independent researchers the organization tasked with carrying out its studies began complaining that Taubes and others were interfering with their research, especially after the studies didn't back Taubes' hypothesis. Today, NuSI is limping along, basically broke and looking for cash – a sad end for what started out as a great and noble idea.
"NuSI collapsed under the weight of its own ideology," Dr. Stephan J. Guyenet, a prominent obesity researcher, wrote. "The nature of ideology is that it’s inflexible when it encounters facts that contradict it. It cannot bend, it can only break."
Taubes isn't entirely off with his widely-read musings on low-carbohydrate diets. There certainly exists evidence that different nutrients and compounds in the foods we eat alter our metabolisms, but the effects are simply not large enough to drive significant weight loss or weight gain. What fuels weight gain is eating more calories than your body uses. What leads to weight loss is eating fewer calories. That's what decades-worth of evidence demonstrates.
Taubes argues that if this is true, Americans – who hear the "eat less and move more" messaging constantly – should be getting thinner over time, not fatter. But there's a simpler explanation: Americans have yet to put this advice into widespread action. Part of the reason might be that they would rather try fad diets like the one that Taubes and many others keep writing so much about.