Good Calories, Bad Calories (60 page)

The vitamin-C molecule is similar in configuration to glucose and other sugars in the body. It is shuttled from the bloodstream into the cel s by the same insulin-dependent transport system used by glucose. Glucose and vitamin C compete in this cellular-uptake process, like strangers trying to flag down the same taxicab simultaneously. Because glucose is greatly favored in the contest, the uptake of vitamin C by cel s is “global y inhibited” when blood-sugar levels are elevated. In effect, glucose regulates how much vitamin C is taken up by the cel s, according to the University of Massachusetts nutritionist John Cunningham. If we increase blood-sugar levels, the cel ular uptake of vitamin C wil drop accordingly. Glucose also impairs the reabsorption of vitamin C by the kidney, and so, the higher the blood sugar, the more vitamin C wil be lost in the urine. Infusing insulin into experimental subjects has been shown to cause a “marked fal ” in vitamin-C levels in the circulation.

In other words, there is significant reason to believe that the key factor determining the level of vitamin C in our cel s and tissues is not how much or little we happen to be consuming in our diet, but whether the starches and refined carbohydrates in our diet serve to flush vitamin C out of our system, while simultaneously inhibiting the use of what vitamin C we do have. We might get scurvy because we don’t faithful y eat our fruits and vegetables, but it’s not the absence of fruits and vegetables that causes the scurvy; it’s the presence of the refined carbohydrates.*96 This hypothesis has not been proven, but, as Wil and Byers suggested, it is both biological y plausible and empirical y evident.

When we discuss the long-term effects of diets that might reverse or prevent obesity, we must not let our preconceptions about the nature of a healthy diet bias the science and the interpretation of the evidence itself.

UNCONVENTIONAL DIETS

Here was a treatment, that, in its encouragement to eat plentiful y, to the ful satisfaction of the appetite, seemed to oppose not only the prevailing theory of obesity but, in addition, principles basic to the biological sciences and other sciences as wel . It produced a sense of puzzlement that was a mighty stimulant to thought on the matter.

ALFRED PENNINGTON, talking about a high-fat, high-protein diet, unrestricted in calories, in the American Journal of Digestive Diseases, 1954

Does it help people lose weight? Of course it does. If you cannot eat bread, bagels, cake, cookies, ice cream, candy, crackers, muffins, sugary soft drinks, pasta, rice, most fruits and many vegetables, you wil almost certainly consume fewer calories. Any diet wil result in weight loss if it eliminates calories that previously were overconsumed.

JANE BRODY, talking about a high-fat, high-protein diet, unrestricted in calories, in the New York Times, 2002

A. J. LIEBLING, THE CELEBRATED AUTHOR of The New Yorker’s “On Press” column, once wrote that he had enunciated a journalistic truth with such clarity that it was suitable for framing. “There are three kinds of writers of news in our generation,” Liebling wrote. “In inverse order of worldly consideration, they are: 1. The reporter, who writes what he sees.

2. The interpretive reporter, who writes what he sees and what he construes to be its meaning.

3. The expert, who writes what he construes to be the meaning of what he hasn’t seen.

“To combat an old human prejudice in favor of eyewitness testimony,” Liebling wrote, “the expert must intimate that he has access to some occult source or science not available to either reporter or reader. He is the Priest of Eleusis, the man with the big picture…. Al is manifest to him, sincehis conclusions are not limited by his powers of observation.”

Leibling was talking about journalism, but a similar ranking holds true in medicine. In fact, the medical experts have the further advantage that they can disseminate their opinions with considerably greater influence. They can make their case with the imprimatur of the institutions that employ them—the American Medical Association, for instance, or Harvard University. They can easily attract the media’s attention. Physicians’ case reports and the patients’ anecdotal experience have a fundamental role in medicine, but if these conflict with what the experts believe to be true, the experts’ opinions win out.

This conflict between expertise and observational evidence has had a significant influence in the science of obesity. Reliable eyewitness testimony has come only from those who have weight problems themselves, or the clinicians who regularly treat obese patients, and neither group has ever garnered much credibility in the field. (The very assumption that obesity is a psychological disorder implies that the obese cannot be trusted as reliable witnesses to their own condition.) But it is these individuals who have the firsthand experience. When Hilde Bruch reported in 1957 that a fine-boned girl in her teens,

“literal y disappearing in mountains of fat,” lost nearly fifty pounds over a single summer eating “three large portions of meat” a day, it was easier for the experts to ignore the testimony as a freakish phenomenon than to contemplate how such a thing was possible. But the process of discovery in science, as the philosopher of science Thomas Kuhn has put it, only begins with the awareness that nature has violated our expectations. Often it is the unconventional events—the anomalous data, as these are cal ed in science—that reveal the true nature of the universe.

In 1920, while Vilhjalmur Stefansson was just beginning his campaign to convince nutritionists that an al -meat diet was a uniquely healthy diet, it was already making the transition into a reducing diet courtesy of a New York internist named Blake Donaldson. Donaldson, as he wrote in his 1962 memoirs, began treating obese patients in 1919, when he worked with the cardiologist Robert Halsey, one of four founding officers of the American Heart Association. After a year of futility in trying to reduce these patients (“fat cardiacs,” he cal ed them) with semi-starvation diets, he spoke with the resident anthropologists at the American Museum of Natural History, who told him that prehistoric humans lived almost exclusively on “the fattest meat they could kil ,” perhaps supplemented by roots and berries. This led Donaldson to conclude that fatty meat should be “the essential part of any reducing routine,”

and this is what he began prescribing to his obese patients. Through the 1920s, Donaldson honed his diet by trial and error, eventual y settling on a half-pound of fatty meat—three parts fat to one part lean by calories, the same proportion used in Stefansson’s Bel evue experiment—for each of three meals a day. After cooking, this works out to six ounces of lean meat with two ounces of attached fat at each meal. Donaldson’s diet prohibited al sugar, flour, alcohol, and starches, with the exception of a “hotel portion” once a day of raw fruit or a potato, which substituted for the roots and berries that primitive man might have been eating as wel . Donaldson also prescribed a half-hour walk before breakfast.

Over the course of four decades, as Donaldson told it, he treated seventeen thousand patients for their weight problems. Most of them lost two to three pounds a week on his diet, without experiencing hunger. Donaldson claimed that the only patients who didn’t lose weight on the diet were those who cheated, a common assumption that physicians also make about calorie-restricted diets. These patients had a “bread addiction,” Donaldson wrote, in that they could no more tolerate living without their starches, flour, and sugar than could a smoker without cigarettes. As a result, he spent considerable effort trying to persuade his patients to break their habit. “Remember that grapefruit and al other raw fruit is starch. You can’t have any,” he would tel them.

“No breadstuff means any kind of bread…. They must go out of your life, now and forever.” (His advice to diabetics was equal y frank: “You are out of your mind when you take insulin in order to eat Danish pastry.”)

Had Donaldson published details of his diet and its efficacy through the 1920s and 1930s, as Frank Evans did about his very low-calorie diet, he might have convinced mainstream investigators at least to consider the possibility that it is the quality of the nutrients in a diet and not the quantity of calories that causes obesity. As it is, he discussed his approach only at in-house conferences at New York Hospital. Among those who heard of his 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 specifical y 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 Col ege 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 wel being.” Al 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 cal ed Pennington’s diet a “believe it or not diet development” and “an eat-al -you-want reducing diet.” Two years later, Pennington discussed his diet at a smal 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 cal s for more extensive and for impartial comparative trials by others”—although, Hegsted concluded, “any method of [obesity] treatment other than caloric restriction stil requires study by al 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 cal ed “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 cal ed

“impartial comparative trials by others” were not necessary. “The proposed high-fat diet wil 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 actual y 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 al owing plenty of protein and fat works excel ently…,”

wrote the prominent British endocrinologist Raymond Greene, “and al ows 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 chal enge 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 al 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 smal 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.”