Good Calories, Bad Calories

^*59 Individuals with a single copy of this apo E4 gene are nearly three times as likely to have both heart disease and Alzheimer’s than those with none. Apo E4 is a cousin of apo B, the protein component of LDL and VLDL, and it is also found in the lipoproteins that transport triglycerides and cholesterol. Because heart-disease researchers have focused on cholesterol as the cause of heart disease, Alzheimer’s researchers tend also to refer to apo E4 as involved in cholesterol transport as though that were all it did, thus “point[ing] to a link between cholesterol and Alzheimer’s.” But this took the overly simplistic 1960s view of heart disease and used it to misdirect the Alzheimer’s research.

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^*60 Harvard neurologist Dennis Selkoe and others have been working to track down a gene that seems to predispose individuals to age-related Alzheimer’s, rather than the inherited early-onset form. By February 2007, they had not found it, but they had localized it, in the lingo, to a chunk of a single chromosome that was known to include the gene for insulin-degrading enzyme. This made IDE the obvious candidate and suggested that anyone who inherited a particularly unlucky variant of the IDE gene would have an increased likelihood of getting Alzheimer’s.

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^*61 Higginson held the environmental movement responsible for what he considered a willful misinterpretation of the epidemiologic observations: “If they could possibly make people believe that cancer was going to result from pollution, this would enable them to facilitate the clean-up of water, of the air, or whatever it is,” he told Science in 1979. He was all for cleaning up the environment, he added, but “to make cancer the whipping boy for every environmental evil may prevent effective action when it does matter.”

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^*62 Those clinical trials that tested the dietary-fat-and-fiber hypotheses of cancer, as we discussed earlier, replaced red meat in the experimental diets with fruits, vegetables, and whole grains. When these trials failed to confirm that fat causes breast cancer, or that fiber prevents colon cancer, they also failed to confirm the hypothesis that red-meat consumption plays a role in either.

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^*63 Tannenbaum actually compared his chronically underfed mice with control mice fed the identical diet but supplemented with cornstarch. The inhibition of cancer, as Tannenbaum noted, could have been due to “carbohydrate-restriction” rather than restriction of all calories.

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^*64 Different IGFs have different effects. To keep the following discussion reasonably simple, I’ll refer to IGF and IGF receptors as though there were only one species of each, although I’m oversimplifying the science by doing so.

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^*65 The apparent severity of this epidemic is inflated by the way in which obesity is defined. The use of a threshold for establishing whether or not you’re obese—a body mass index (BMI) of 30—means that one can move from the overweight category to the obese category by virtue of gaining a few pounds. As a result, the 10-percent rise in obesity between 1991 and 2000 actually represented an increase in the average BMI of Americans from 26.7 to 28.1, an average weight gain of seven to ten pounds.

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^*66 Between the second and third National Health and Nutrition Examination Study.

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^*67 The USDA has a variety of mechanisms for estimating macronutrient intake—i.e., protein, carbohydrates, and fat—and has published a variety of reports on the subject. Not all are consistent, but the findings on fat consumption are. For instance, in April 1998, the USDA published an article entitled “Is Total Fat Consumption Really Decreasing?” This article reported that average total fat consumption for men aged nineteen to fifty, for instance, dropped from 113 grams per day in 1977–78 to ninety-six in 1989, the period that encompasses the beginning of the obesity epidemic. The relevant numbers for women of the same age group are seventy-three grams of fat per day in 1977–78 and sixty-two in 1989.

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^*68 According to the Sporting Goods Manufacturers Association, sales of sporting equipment, apparel, and shoes increased from $21.9 billion in 1987 (the earliest year for which they have data) to $52 billion in 2004.

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^*69 If each Pima drank two eight-ounce soft drinks a day, this would add roughly two hundred calories a day to Hesse’s estimate of both carbohydrate and calorie consumption, and so would drop the fat in the diet to 22 percent.

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^*70 The Sioux were “essentially carnivorous” prior to their reservation life, the report noted, and so they “were never in the habit of eating much fruit and vegetables.”

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^*71 Hrdlika did publish a list of diseases treated by the local agency physician, which did include one case of diabetes.

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