of more recent commercial vintage and exploitation. The latest studies suggest that its effects are as bad as those of sucrose,11 if not worse.12
In order to use this evidence in support of the low-carb movement, Taubes performs a bit of sleight of hand, the crux of which is: refined sugar is bad, therefore all foods that contain sugars (i.e., carbs) are bad. This is poor logic even in the classical sense. We can also highlight the flaws in this reasoning by considering another carbohydrate found in plant food—fiber—and comparing its health effects when in its natural state and when processed, isolated, and consumed as a substance separate from that natural state.
Dietary fiber is extracted from all kinds of whole plants in order to add it to muffins and other baked goods as “bran.” Marketers then claim health benefits from these baked goods, citing the research evidence on the goodness of fiber. But bran doesn’t help us when it’s been extracted from whole plants and then stuck into processed and fragmented foods like breads and breakfast cereals. Although there is some evidence that bran supplements may reduce certain indicators of serious health problems, I find no evidence that, over the long term, this is a good option for actually preventing or treating these problems.13
Whole foods that contain dietary fiber, in its many complex forms, are associated with lower incidence of colon cancer, lower blood cholesterol, and lower breast cancer–inducing estrogen levels. The use of bran isolated from these foods is more about marketing than health. This holds true for many isolated nutrients, which either have no positive health benefits or actually result in damaging effects.
If Taubes and his low-carb compatriots are against ingesting refined (i.e., extracted) sugars, they should say so, and I’d be among the first to support their crusade to eliminate those sugars from our diets. But instead, they tar the entire class of carbohydrates with the same brush, which is an intellectually superficial and dishonest move. (Taubes is more careful than some other low-carb cheerleaders, but not completely so. He should be proactively emphasizing this discrepancy, not allowing it to smolder just below the public narrative.)
Because fruits, vegetables, and whole grains are all high in carbohydrates, lumping all carbs together as unhealthy means demonizing plant-based foods as well as simple sugars. A diet low in carbohydrates is unavoidably a diet high in fat, especially saturated fat, because eliminating carbohydrates means relying on large quantities of animal-based products for energy and other nutritional benefits. Virtually by definition, therefore, a low-carb diet emphasizes the consumption of animal-based foods, while a low-fat diet emphasizes the consumption of plant-based foods. In my experience, it is this emphasis given to animal-based foods in low-carb (and thus high-protein, high-fat) diets that is the chief motivation of low-carb advocates.
The dramatic shift in consumption suggested by Taubes’ oversimplification of the definition and meaning of carbohydrates has momentous consequences. Not only does shifting to a diet low in carbs severely minimize our intake of antioxidants, complex carbohydrates, vitamins, and certain minerals, it also shifts our dietary source of energy from carbohydrates to fat and encourages consumption of protein far above the required amount.
Why is this such a terrible thing? Because the foods we choose to meet our energy needs make a big difference in whether we experience good or ill health.
Number of Calories Versus Source of Calories
If by “good and bad calories,” Taubes means “good and bad sources of energy”—in effect, good and bad foods—he and I agree, at least in principle. Plant- and animal-based foods are hugely different in terms of their nutrient contents, and watching what foods you consume is far more important than obsessing over calorie-counting without respect to where those calories come from.
Take, for example, our research into the effect of dietary protein on cancer growth in experimental animals, involving about twenty-five individual experiments conducted over about thirty years. The animals consuming the lowest amount of protein (5 percent of total calories) had far less cancer than their higher-protein-consuming counterparts, while consuming an average of 2 to 3 percent more total calories (or, as I prefer to say, more total energy). This is an important observation: more calories consumed, but less cancer.
It was not easy to convince some of my colleagues of this finding because of their long-standing and almost certain belief that our conclusion should have been exactly the opposite: that increased calories lead to increased rates of cancer (as well as other disease). These beliefs on the calorie-cancer connection were based on prior experimental studies, which showed reduced cancer occurrence when calorie consumption was reduced by a hefty 20 to 30 percent or more.14
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