Good Calories, Bad Calories

Neither the individuals who wish to lose weight nor the clinicians who prescribe the diet need a randomized trial to tell them if it works. Such a trial is necessary only to establish that the diet works better than some other diet, and whether it leads to sustained benefits in health and longevity.

Until recently, few nutritionists or clinicians considered it worth their time and effort to test weight-reducing diets. Instead, they spent their careers studying the physiological and psychological abnormalities associated with the condition of obesity, comparing food consumption and physical activity in obese and lean individuals, and studying obesity in animals. They tried to induce fat people to endure semi-starvation by behavioral modification; they studied pharmacological methods of suppressing hunger, or surgical methods of reducing the amount of food that could be consumed or digested.^*101 Testing diets or even treating obese patients was regarded as lesser work. “To be honest, obesity treatment is extremely boring,” said Per Björntorp, who was among the most prominent European authorities on obesity in the 1970s and 1980s. “It’s very difficult and unrewarding.” When obese individuals came to his biochemistry laboratory at the University of Göteborg, they were referred to the local nutritionists to be taught how to count and restrict calories. Since everyone knew that obesity was caused by overeating, why bother with diet trials? “There’s no point wasting your time on them,” George Bray, considered one of the world’s leading authorities, said in a recent interview. “If you get restriction of energy you will lose weight, unequivocally. It’s not an issue.”

When clinical investigators did test the efficacy of high-fat, carbohydrate-restricted diets, however, the results were remarkably consistent. Every investigator reported weight losses of between one and five pounds a week even when the investigators running the trial seemed more concerned with establishing that the diets caused deleterious side effects. Every investigator who discussed the subjective experiences of the test subjects reported that they suffered none of the symptoms of semi-starvation or food deprivation—“excessive fatigue, irritability, mental depression and extreme hunger,” as Margaret Ohlson described them.

The last of these symptoms may be the most telling. The diets induced significant weight loss without hunger even when the patients ate only a few hundred calories a day, as Russell Wilder’s did at the Mayo Clinic in the early 1930s, or 650–800 calories per day, as was the case with the patients treated by George Blackburn and Bruce Bistrian of MIT’s department of nutrition and food science and the Harvard Medical School in the 1970s. Wilder was treating his obese patients with the very low-calorie diet developed by Frank Evans, principally meat, fish, and egg white, with 80–100 calories’ worth of green vegetables. “The absence of complaints of hunger has been remarkable,” Wilder wrote. Bistrian and Blackburn reported in 1985 that they had prescribed their diet of lean meat, fish, and fowl—almost 50 percent protein calories and 50 percent fat—to seven hundred patients. On average, the patients lost forty-seven pounds over a period of four months; nearly three pounds a week. “People loved it,” said Blackburn.^†102

Significant weight loss without hunger was also reported when the diet was prescribed at 1,000 calories, as the University of Würzburg clinicians Heinrich Kasper and Udo Rabast did in a series of trials through the 1970s; at 1,200 calories, as the University of Iowa nutritionist Willard Krehl reported in 1967; at 1,320 calories, as Edgar Gordon of the University of Wisconsin reported in JAMA in 1963; at 1,400 or 1,800 calories, as Young and Ohlson did; at 2,200 calories, as the Swedish clinician Bertil Sjövall reported in 1957, and even when the diet provided more than 2,700 calories a day, as reported also in 1957 by Weldon Walker, who would later become chief of cardiology at the Walter Reed Army Medical Center in Washington. The same has invariably been the case even when patients are simply “encouraged to eat as much as [is] necessary to avoid feeling hungry,” but to avoid carbohydrates in doing so, as John LaRosa, now president of the State University of New York Downstate Medical Center, reported in 1980.