Related: Trusting Expert Consensus

Lately, I've been thinking a lot about whether we can find any clear exceptions to the general "trust the experts (when they agree)" heuristic. One example that keeps coming up—at least on LessWrong and related blogs—is Gary Taubes' claims about mainstream nutrition experts allegedly getting obesity horribly wrong.

Taubes is probably best-known for his book Good Calories, Bad Calories. I'd previously had a mildly negative impression of him from discussion of him on Yvain's old blog, particularly some of other posts Yvain and other people linked from there, such as this discussion of Taubes' "carbohydrate hypothesis" and especially this discussion of Taubes' attempt to refute the standard calories-in/calories-out model of weight.

But I figured maybe the criticism of Taubes I'd read hadn't been fair to him, so I decided to read him for myself... and holy crap, Taubes turned out to be far worse than I expected. I decided to write a post explaining why, and then realized that, even if I were somewhat selective about the issues I focused on, I had enough material for a whole series of posts, which I'll be posting over the course of the next week.

The problem with Taubes is not that everything he says is wrong. Much of it is ludicrously wrong, but that's only one half of the problem. The other half is that he says a fair number of things mainstream nutrition science would agree with, but then hides this fact, and instead pretends those things are a refutation of mainstream nutrition science. So it's worth starting with a brief in-a-nutshell version of what mainstream nutrition science actually says about obesity.

(The following summary is drawn from a number of sources, including this, this, and this. Everything I'm about to say will be discussed in much greater detail in subsequent posts.)

Here it goes: people gain weight when they consume more calories than they burn. But both calorie intake and calorie expenditure are regulated by complicated mechanisms we don't fully understand yet. This means the causes of overweight and obesity* are also complicated and not fully understood. It is, however, worth watching out for foods with lots of added fat and sugar, if only because they're an easy way to consume way too many calories.

We currently don't have any great solutions to the problem of overweight and obesity. If you consume fewer calories than you burn, you will lose weight, but sticking to a diet is hard. It's relatively easy to lose weight in the short run, and it's possible to do so on a wide variety of diets, but only a small percentage of people keep the weight off over the long run.

As for low-carb diets, people do lose weight on them, but they do so because low-carb diets generally lead people to restrict their calorie intake even when they aren't actively counting calories. For one thing, it's hard to consume as many calories when you drastically restrict the range of foods you can eat. There's also some evidence that low-carb diets may have some advantages. in terms of, say, warding off hunger, but the evidence is mixed. There's certainly no basis for claiming low-carb diets as a magic bullet for the problems of overweight and obesity.

The above points are not the only issues at stake in Taubes' writings on nutrition. Admittedly, he covers a huge amount of ground, from the relationship between sugar and diabetes to the relationship between fat intake and heart disease to the alleged dangers of extremely-low carbohydrate diets. However, I'll be focusing on his claims about the causes of and solutions to the problems of overweight and obesity, because that seems to be the main thing people talk about when they talk about Taubes supposedly showing how wrong mainstream experts can be.

I'll also focus heavily on how Taubes misrepresents the views of mainstream experts on obesity. In the next post, though, I'll be temporarily setting that issue aside in order to look at what Taubes is proposing as an alternative. This will involve examining some claims made by Dr. Robert Atkins, whose ideas' Taubes champions.

*Note: if the use of "overweight" as a noun sounds weird to you, it does to me too, but I discovered as I researched this article that it's standard usage in the literature on the subject. I came to realize there's a good reason for this usage: it's inaccurate to talk about the problem solely in terms of "obesity," but constantly saying "the problem of people being overweight and obese" gets really wordy.

Next: Atkins Redux