treatment, however, was Alfred Pennington, a local internist who tried the diet himself in 1944—and then began prescribing it to his patients.
After the war, Pennington worked for the industrial-medicine division of E. I. du Pont de Nemours & Company, and specifically for George Gehrmann, the company’s medical director and a pioneer in the field of occupational health.*97 Gehrmann founded and was the first president, from 1946 to 1949, of the American Academy of Occupational Medicine, an organization that has since merged and evolved into the American College of Occupational and Environmental Medicine. By 1948, according to Gehrmann, DuPont as a corporation had become anxious about the apparent epidemic of heart disease in America. Just as Ancel Keys said he was prompted to pursue dietary means to prevent heart disease after perusing the obituaries, Gehrmann said he was prompted by the heart attack of a DuPont executive. Gehrmann decided to attack overweight and obesity, hoping heart-disease risk would diminish as a result.
“We had urged our overweight employees to cut down on the size of the portions they ate,” Gehrmann said, “to count their calories, to limit the amounts of fats and carbohydrates in their meals, to get more exercise. None of those things had worked.” These failures led Gehrmann and Pennington to test Donaldson’s meat diet on overweight DuPont executives.
In June 1949, Pennington published an account of the DuPont experience in the journal Industrial Medicine. He had prescribed Donaldson’s regimen to twenty executives, and they lost between nine and fifty-four pounds, averaging nearly two pounds a week. “Notable was a lack of hunger between meals,” Pennington wrote, “increased physical energy and sense of well being.” All of this seemed paradoxical: the DuPont executives lost weight on a diet that did not restrict calories. The subjects ate a minimum of twenty-four hundred calories every day, according to Pennington: eighteen ounces of lean meat and six ounces of fat divided over three meals. They averaged over three thousand calories. Carbohydrates were restricted in their diet—no more than eighty calories at each meal. “In a few cases,” Pennington reported, “even this much carbohydrate prevented weight loss, though an ad-libitum [unrestricted] intake of protein and fat, more exclusively, was successful.”*98
In June 1950, Holiday magazine called Pennington’s diet a “believe it or not diet development” and “an eat-all-you-want reducing diet.” Two years later, Pennington discussed his diet at a small obesity symposium hosted by the Harvard department of nutrition and chaired by Mark Hegsted. “Many of us feel that Dr. Pennington may be on the right track in the practical treatment of obesity,” Hegsted said afterward. “His high percentage of favorable results is impressive and calls for more extensive and for impartial comparative trials by others”—although, Hegsted concluded, “any method of [obesity] treatment other than caloric restriction still requires study by all methods that can be brought to bear on the problem.”
The Harvard symposium led to the publication of Pennington’s presentation in The New England Journal of Medicine, and this, along with the Vogue article, prompted the competing medical journals to address it. In a scathing editorial called “Freak Diets!” The Journal of the American Medical Association (JAMA) took the position that calorie restriction was the only legitimate way to induce weight loss, and that what Hegsted had called “impartial comparative trials by others” were not necessary. “The proposed high-fat diet will probably add unduly to the patient’s weight and thus, in addition to the other harmful effects of obesity, increase the hazard of atherosclerosis,” wrote JAMA. In Britain, The Lancet wrote, “A low calorie intake is the best way to restore the composition of the body to normal, and this is most easily arranged by eliminating fat from the diet.” If Pennington’s diet worked, according to The Lancet, it did so only because “any monotonous diet leads to a loss of weight.”
Clinicians—doctors who actually treated obese patients—pushed back against the experts. After The Lancet’s editorial, local clinicians wrote that the diet was successful in “a surprisingly large proportion of cases,” as one Devonport physician put it. “Results so far certainly seem to support the work of Pennington which you rather lightly dismiss.” “Pennington’s idea of cutting out the carbohydrate but allowing plenty of protein and fat works excellently…,” wrote the prominent British endocrinologist Raymond Greene, “and allows of a higher caloric intake than a proportionate reduction of protein, fat and carbohydrate…. The diet need not be monotonous. Many patients come to prefer it.” By early 1954, The Lancet’s editors were backpedaling, just as they had with Banting a century earlier. “Pennington has hardly proved his case,” the journal argued, but it accepted the possibility that his diet worked, and perhaps not through the usual method of restricting calories.
The challenge to JAMA came from a physician within the American Medical Association itself—from George Thorpe, a Kansas doctor who both treated obese patients and chaired the AMA’s Section on General Practice. At the AMA annual meeting in 1957, Thorpe charged that semi-starvation diets would inevitably fail, because they work “not by selective reduction of adipose deposits, but by wasting of all body tissues,” and “therefore any success obtained must be maintained by chronic undernourishment.” Thorpe had tried Pennington’s diet, he said, after “considering a personal problem of excess weight.” He then began prescribing the diet to his patients, who experienced “rapid loss of weight, without hunger, weakness, lethargy or constipation.” Even with small portions of salad and vegetables included, Thorpe said, weight losses of six to eight pounds a month could be obtained. “Evidence from widely different sources,” he concluded, “seems to justify the use of high-protein, high-fat, low-carbohydrate diets for successful loss of excess weight.”
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
