In his New York Times science column this week, John Tierney takes on the idea that calories from fat are especially bad for you. Gram for gram, fat does provide more calories than protein or carbohydrates do. But critics of low-fat diet advice have long argued that total calories are what matters for people concerned about their weight, and that overemphasizing fat reduction can actually encourage overeating (as when people gorge themselves on "low-fat" snacks that have about the same calorie content as the standard versions). In his book Good Calories, Bad Calories (which Tierney has read but I have not), science writer Gary Taubes goes further, questioning the conventional wisdom that fat consumption contributes to heart disease. Tierney agrees with Taubes (who is famous/notorious for his 2002 New York Times Magazine cover story suggesting that high-fat, low-carb guru Robert Atkins was onto something) that physicians rushed to judgment about the cardiovascular impact of fat consumption. Tierney describes the anti-fat consensus as the result of an erroneous "informational cascade," in which a few prominent endorsements triggered an avalanche of authoritative statements with little scientific basis.
Tierney is not so sure about Taubes' attempt to vilify carbs instead of fat, and I share his skepticism. Are we condemned to forever swing between these two extremes of nutritional wisdom? Is it possible that the boring old advice about a balanced, omnivorous diet is closer to the truth after all? Or maybe it's just the safest course in the face of uncertainty.