Good Calories, Bad Calories

In response to Thorpe’s testimonial, JAMA could no longer claim outright that a high-fat, carbohydrate-restricted diet would actually increase weight, as it had asserted five years earlier, but it still insisted in a 1958 editorial that the diet would endangered health, whatever else it might accomplish.^*99 Pennington’s diet failed to fulfill the criterion of being “adequate in all essential nutrients,” JAMA wrote. Thus, “the most reasonable diet to employ for weight reduction is one that maintains normal proportions of fat, proteins, and carbohydrates and simply limits the total quantity of the mixture.” As it would do for the next fifty years, JAMA disregarded firsthand testimony from clinicians and trivialized the scientific issues; it promoted diets not because they were effective, but because they were supposedly “least harmful”—invariably basing its notion of harm on ideas that had been and would be strongly challenged for decades.

All the while, the DuPont experience would be confirmed in the literature repeatedly. The first confirmation came from two dietitians, Margaret Ohlson and Charlotte Young, who published their observations in the Journal of the American Dietetic Association in 1952. Ohlson was chair of the food and nutrition department at Michigan State University. Young had studied with Ohlson in the 1940s and then moved to Ithaca, New York, to become a nutritionist at Cornell. Young also worked with Cornell’s Student Medical Clinic, and it was in this capacity, along with struggles to control her own weight (she was five ten and weighed 260 pounds), that she had become dissatisfied with calorie-restricted diets.

Ohlson began her research by testing Pennington’s diet on members of her own laboratory. “The edibility of the food mixture, the feeling of well-being of the subjects and the ease with which meal pattern could be fitted into a daily schedule involving business and social engagements, suggested a further trial with patients,” Ohlson reported. She then prepared a version of Pennington’s diet that restricted both carbohydrates and calories, on the mistaken assumption that the diet must work by restricting calories. This was the diet that Young would also use at Cornell. It allowed only fourteen to fifteen hundred calories a day, out of which 24 percent was protein, 54 percent was fat, and 22 percent was carbohydrates.^*100 Because the diet was also calorie-restricted, it did not actually test Pennington’s observation that weight would be lost even without such a calorie limitation. Nor did Ohlson or Young address the question of why their subjects never reported feeling hungry even though it provided no more calories than a typical semi-starvation diet. Still, their observations are relevant, particularly because they came in an era when high-fat diets were not yet widely considered deadly, so that researchers were not biased by this perception.

Ohlson initially tested a twelve-hundred-calorie low-fat diet on four overweight young women. This was eight hundred to a thousand calories less than these women normally ate to maintain their weight, Ohlson reported, so they should have lost at least twenty-two pounds each over the fifteen weeks of the trial. Rather, the four women lost zero, six, seven, and seventeen pounds. The “subjects reported lack of ‘pep’ throughout…[and] they were discouraged because they were always conscious of being hungry.”

Ohlson then tested her calorie-restricted version of Pennington’s diet on seven women who ranged from mildly overweight to obese. These women followed the diet for sixteen weeks and lost between nineteen and thirty-seven pounds. In a comparison of the low-fat diet of twelve hundred calories with the carbohydrate-restricted diet of fourteen to fifteen hundred calories, the former resulted in an average weight loss of a half-pound a week, whereas the latter diet, higher in calories, induced an average weight loss of almost three pounds weekly. “Without exception, the low-carbohydrate reducing diet resulted in satisfactory weight losses,” Ohlson wrote. “The subjects reported a feeling of well-being and satisfaction. Hunger between meals was not a problem.”