Previously: Mainstream Nutrition Science on Obesity, Atkins Redux

Here's where I start talking about the thing that initially drove me to write this post series: Taubes' repeated misrepresentation of the views of the mainstream nutrition authorities he attacks. I'll start by going back to Taubes' 2002 article. Immediately after the discussion of Atkins, it contains another set of claims that stood out to me as a huge red flag: 

Thirty years later, America has become weirdly polarized on the subject of weight. On the one hand, we've been told with almost religious certainty by everyone from the surgeon general on down, and we have come to believe with almost religious certainty, that obesity is caused by the excessive consumption of fat, and that if we eat less fat we will lose weight and live longer. On the other, we have the ever-resilient message of Atkins and decades' worth of best-selling diet books, including ''The Zone,'' ''Sugar Busters'' and ''Protein Power'' to name a few. All push some variation of what scientists would call the alternative hypothesis: it's not the fat that makes us fat, but the carbohydrates, and if we eat less carbohydrates we will lose weight and live longer.

The perversity of this alternative hypothesis is that it identifies the cause of obesity as precisely those refined carbohydrates at the base of the famous Food Guide Pyramid -- the pasta, rice and bread -- that we are told should be the staple of our healthy low-fat diet, and then on the sugar or corn syrup in the soft drinks, fruit juices and sports drinks that we have taken to consuming in quantity if for no other reason than that they are fat free and so appear intrinsically healthy. While the low-fat-is-good-health dogma represents reality as we have come to know it, and the government has spent hundreds of millions of dollars in research trying to prove its worth, the low-carbohydrate message has been relegated to the realm of unscientific fantasy.

I'll start with the obvious: We thought sugary soft drinks were intrinsically healthy? To quote an old joke, who do you mean we, kemosabe? Given widespread scientific illiteracy, I wouldn't be surprised if some people have believed that low-fat is a sufficient condition for being healthy, but if so, they didn't get this idea from mainstream nutrition science.

Taubes makes it sound the mainstream view and the view Atkins pushed are mirror images of each other: on the one hand, "everyone from the surgeon general on down" told us "if we eat less fat we will lose weight and live longer." On the other hand, Atkins et al. told us "if we eat less carbohydrates we will lose weight and live longer."

This rhetoric ignores a crucial distinction: as I showed in my previous post, Atkins really did claim eating less carbs was a sufficient condition for weight loss, and that no amount of fat could possibly make us fat. Mainstream nutrition experts, on the other hand, did argue low fat diets were better for us, all else being equal. But they never, so far as I've been able to find, claimed a low-fat diet was a sufficient condition for losing weight, or that no amount of sugar could possibly make make us fat.

Taubes seems unaware of this—or else he chooses to hide it from his readers. In Good Calories, Bad Calories (p. 342), for example, he attempts to rebut the suggestion that low-carb diets are really low-calorie diets in disguise that this idea "seems to contradict the underlying principle of low-fat diets for weight control and the notion that we get obese because we overeat on the dense calories of fat in our diets." This response would only make sense if mainstream nutrition scientists were saying eating less fat is the be-all, end-all of weight loss.

In these initial paragraphs, Taubes only cites one source for what mainstream nutrition experts were supposedly telling us: the USDA's Food Guide Pyramid. This is an unfortunate choice, because as anyone who's actually seen the chart knows, sweets get put right up at the top with fats and oils under the "use sparingly" category. At this point in the article, I wonder how anyone reading it could avoid suspecting something was. (The same goes for the references to the Food Pyramid in Taubes' books on nutrition, both of which quote the "use sparingly" recommendation in regard to fats and oils, while carefully omitting the fact that it said the same thing about sweets.)

But then again, the Food Pyramid was first published the year I entered kindergarten, so I'm at exactly the right age to have had it drilled into my head hard in school. And maybe mainstream nutrition messaging was much crazier in the 70's and 80's. So what about the other sources Taubes cites as supposedly showing mainstream nutritionists giving giving us terrible advice about fat vs. sugar? 

Farther down in the article, Taubes talks about how the debate over the 1977 Senate committee report "Dietary Goals for the United States" supposedly tried to settle the debate over what Taubes calls the "low-fat-is-good-health dogma" with politics rather than science. Yet a quick look at the report reveals it's statements to the effect that fat is dangerous and we should eat less of it are consistently paired with parallel statements about sugar, including a recommendation to cut our sugar intake by 40 percent. Instead, the report recommends, we should be eating more fruits, vegetables, and whole grains.

Okay, what about the sources Taubes cites in his books? Three important ones are summarized in the chapter on sugar in Good Calories, Bad Calories:

In 1986, the FDA exonerated sugar of any nutritional crimes on the basis that "no conclusive evidence demonstrates a hazard." The two-hundred-page report constituted a review of hundreds of articles on the health aspects of sugar, many of which reported that sugar had a range of potentially adverse metabolic effects related to a higher risk of heart disease and diabetes. The FDA interpreted the evidence as inconclusive. Health reporters, the sugar industry, and public-health authorities therefore perceived the FDA report as absolving sugar of having any deleterious effects on our health.

The identical message was passed along in the 1988 Surgeon General’s Report on Nutrition and Health and the 1989 National Academy of Sciences Diet and Health report.

Let's start with the FDA report. If you read the executive summary (which I obtained thanks to a generous individual on r/scholar), a couple things stand out. They continually emphasize that they were interested in whether sugar was harmful at current levels (i.e. in 1986, more than 25 years ago), and whether sugar had a unique role in the cause of obesity. There's nothing to suggest that increasing our sugar consumption (which we in fact did, along with increasing our intake of calories in general) would be harmless.

The 1988 Surgeon General's report is even less impressive as an example of supposed official sanction for sugar consumption. The summary of recommendations (p. 3) recommends that people "Reduce consumption of fat (especially saturated fat) and cholesterol," but recommends replacing high-fat foods not with just any carbohydrates, but with whole grains, fruits, and vegetables. It also recommends, on the subject of weight control, that people "limit consumption of foods relatively high in calories, fats, and sugars, and to minimize alcohol consumption." Similarly, the 1989 National Academy of Sciences Diet and Health report (p. 18) explicitly recommends replacing fat with whole grains rather than food and drinks containing added sugars. 

One other example bears mentioning. In Why We Get Fat, Taubes claims:

[Low-fat] logic may have reached the pinnacle of absurdity in 1995 (at least I hope it did), when the American Heart Association published a pamphlet suggesting that we can eat virtually anything with impunity—even candy and sugar—as long as it's low in fat: "To control the amount and kind of fat, saturated fatty acids and dietary cholesterol you eat," the AHA counseled, "choose snacks from other food groups such as... low-fat cookies, low-fat crackers... unsalted pretzels, hard candy, gum drops, sugar, syrup, honey, jam, jelly, marmalade (as spreads)." (p. 162)

The pamphlet Taubes is referring to can be found here. The two halves of the above "quote" ("To control the amount and kind of fat, saturated fatty acids and dietary cholesterol you eat" and the second part that begins "chose snacks from other food groups...") are separated by a dozen pages of boringly mainstream advice which closely resembles that of the Food Guide Pyramid: no more than 6 ounces of lean meat per day; 5 or more servings of fruits and vegetables a day; 2 or more servings of dairy; and 6 or more servings of bread, cereals, pasta, and starchy vegetables.

The part that Taubes ridicules about low-fat cookies and so on comes from a section on snacks that doesn't come with a recommended number of daily servings. I suppose if you read the AHA pamphlet knowing nothing else about nutrition, you could take that as a sign that the listed snacks are wonderfully healthy and you should eat as much of them as you like. But anyone familiar with the standard nutrition advice of the time would understand that the intended meaning is "if you snack, choose the low-fat options"—not that you should necessarily be snacking much at all. That may or may not have been good advice, but it's not nearly so absurd as Taubes makes it out to be.

It's possible there's room here to criticize not the underlying science, but the science communication; not what the official reports and said, but how well that information was conveyed to the general public, few of whom are likely to have read the original reports carefully. If a significant number of people really did believe eating less fat was all they needed to do to lose weight and that Coca-Cola is "intrinsically healthy" (as Taubes claims "we" believed), we'd have an example of a serious failure of science communication.

Any such criticisms of science communication side of things would need to be tempered with recognition that science communication is really freaking hard. If you haven't seen the amount of hand-wringing that's gone on in the science and skepticism blogosphere over how to do science communication better, trust me: scientists have thought a lot about this stuff, and it's not obvious what the solutions are. Yet if bad science communication were really, say, a major contributing factor in the obesity epidemic, it would underline the need for scientists to do their absolute best in communicating with the general public.

But a failure of science communication isn't how Taubes frames his attack on mainstream nutrition authorities, nor is it the message most people seem to take away from reading his work. Taubes' irresponsible rhetoric doesn't help the problem of bad science communication—it adds to it.

Next: What Causes Obesity?