by Marion Nestle
Sep 16 2007

Does Nutritional Epidemiology Work?

If you have some time, take a look at Gary Taubes’ thoughtful piece on epidemiology in Sunday’s New York Times Magazine. His new book, Good Calories, Bad Calories, comes out in a couple of weeks and I am eager to read it. I’m just keeping fingers crossed that it doesn’t start another low-carb craze the way his “Big Fat Lie” piece did in the New York Times magazine five years ago.

  • WaltK

    The epidemiology piece was on the dry side, but a fascinating discussion of the limitations of the discipline. It seems to suggest that if there are such difficulties with relatively narrow interventions such as a drug administration, trying to apply epidemiology to nutrition will be hopelessly confounded — especially when trying to extrapolate the findings to any individual. It was revealing to get some idea of the magnitude of effects, such as the statements like “reduces the risk of cancer by 30%”. That’s actually quite a tiny effect, and difficult to interpret meaningfully.

    From what I hear from advance readers of Taubes’s new book, it’s quite unsettling in that it suggests the evidence behind the accepted ‘truths’ in nutrition is often flimsy or wildly overstated, and highly colored by fashion and politics. And there is a suprisingly large amount of contrary data that is pretty much ignored, because it is out of vogue or difficult to reconcile with the prevailing view. At least it might be a good, objective look at the evidence behind what everyone seems to ‘know’ about diet. It’s supposedly exhaustively documented. But I havent’

    When you say “I hope it doesn’t start a new low-carb craze” it sounds a bit like what Gary Taubes has been critiquing in nutrition science.

    It sounds almost you’re saying “I hope it doesn’t show there is evidence for the value of reducing carbohydrate. We hate that idea.” That’s what I think is scary about nutrition research.

    Would you prefer it to re-kindle the “low-fat craze”, or a “portion-control mania”, or a “vegetarian fad”, or a “eat mostly plants craze”?

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  • I’m eager to read Taube’s new book, too (I’ve preordered a copy after waiting for more than a year for a publication date). Some bloggers I follow have read drafts and advance copies and have very good things to say about the book (which doesn’t surprise me as Taubes is an excellent journalist). I’m pinning a lot of hope on this book illuminating the nonsense that passes for advice on health these days.

    But low carb craze? The only problem I saw with the all the attention paid to low carb diets a few years back was that people didn’t do it right, therefore it didn’t work for them. They tried to do low carb without understanding what they were doing, with too many compromises and shortcuts. Most people I knew who claimed to be eating low carb weren’t really eating low carb, certainly not the way I understand it and have done it for about 4 years. They just reduced potatoes, bread, and pasta and instead ate junky processed foods like low carb tortilla chips, low carb pastas, sugar-free chocolate, and low carb muffins (and the food processors obliged them with all kinds of low carb junk). In fact some increased their consumption of processed foods because the labels said low carb (just like the Snackwell low-fat syndrome). They probably also had some nasty side effects from the increased fractionated soy ingredients and sugar alcohols they were consuming.

    Another problem is that people were still afraid of fat, so they cut carbs and continued to restrict fat. There goes the energy, not to mention the flavor, satiety, and texture. And the body doens’t like too many mixed sources of energy. Fat has one metabolism, carbs have another. Our bodies are more happy with one primary fuel, not simultaneous hybrid systems.

    By and large, eating low carb healthily and successfully means eating real food, prepared from scratch, not packaged food that has “low carb” labels all over. It means realizing that many of the carbs they are eating can be eliminated, not merely replaced with an ersatz low carb versions. For instance, all those sandwich fixings can be eaten without a vehicle like bread (or open face with one slice of bread). Forks, knives, & spoons are as useful as bread and fingers for transporting food into the mouth. Eliminating the starch makes room for more vegetables, too.

    The book is due out September 25, according to Amazon.

  • Bix

    “And the body doens’t like too many mixed sources of energy. … Our bodies are more happy with one primary fuel, not simultaneous hybrid systems.”

    Is this true?

  • Surely that did not come out of Taubes’ article? I’d say metabolism is set up to happily use any fuel that comes its way–protein, fat, or carbohydrate–and it couldn’t care less if they are mixed. Very efficient, this system.

  • Fentry

    This was a wonderful, fascinating article–particularly since it was a piece of journalism. I wish they were all like this!