Good Calories, Bad Calories

Among the few investigators whose careers spanned the war years, Louis Newburgh was the most influential and conspicuous. As late as 1948, Newburgh was still promoting his perverted-appetite hypothesis of obesity. The first obesity textbook published after the war, Obesity… (1949), by Edward Rynearson and Clifford Gastineau, would be considered the standard text on obesity for twenty years. It faithfully communicated Newburgh’s belief that obesity is caused by overeating. Any suggestion to the contrary, wrote Rynearson and Gastineau, constituted little more than “an excuse for avoidance of the necessary corrective measures.”

An entire generation of young researchers and clinicians effectively started the study of obesity from scratch after the war. They did so with little concern for whatever understanding had been achieved before they arrived, and so they embraced a hypothesis of causation that flew in the face of much of the evidence. The institutionalized skepticism and meticulous attention to experimental detail that are necessary to do good science—“being ruthless in self-criticism and…taking pains in verifying facts,” as the Nobel laureate chemist Hans Krebs said—had also been left behind.

Chapter Twenty-two

THE CARBOHYDRATE HYPOTHESIS, II: INSULIN

Every woman knows that carbohydrate is fattening.

REGINALD PASSMORE AND YOLA SWINDELLS, British Journal of Nutrition, 1963

The fact that insulin increases the formation of fat has been obvious ever since the first emaciated dog or diabetic patient demonstrated a fine pad of adipose tissue, made as a result of treatment with the hormone.

REGINALD HAIST AND CHARLES BEST, The Physiological Basis of Medical Practice, 1966

IN 1929, WHEN LOUIS NEWBURGH FIRST rejected the possibility of an “endocrine abnormality” as the cause of obesity, and insisted instead that all fat people had a perverted appetite, hormones were still widely known as “internal secretions” and endocrine glands as “ductless glands.” The first purification of growth hormone had been only nine years earlier, the purification of insulin only eight years before. In 1955, when The Journal of the American Medical Association declared unconditionally that those “theories that attributed obesity to an endocrine disturbance have been shown to be erroneous,” it was five years before Rosalyn Yalow and Solomon Berson would publish the details of the first method for measuring the insulin level in the blood, and a few more years after that before the ensuing revelations that obesity was associated with the endocrine disturbances and abnormalities of hyperinsulinemia and insulin resistance.

In other words, the editors at JAMA—and the clinical investigators they represented—were declaring that hormones, as a rule, play little role in the genesis of obesity, even before the relevant hormones could be measured accurately in the human bloodstream. In fact, it’s hard to imagine, as Julius Bauer noted, that hormones wouldn’t play a role. Here again we have that familiar scenario we first discussed with regard to dietary fat and heart disease. Once the “truth” has been declared, even if it’s based on incomplete evidence, the overwhelming tendency is to interpret all future observations in support of that preconception. Those who know what the answer is lack the motivation to continue looking for it. Entire fields of science may then be ignored, on the assumption that they can’t possibly be relevant.

In 1968, Jean Mayer pointed out that obesity researchers may have “eliminated” hormones “from legitimate consideration” as a cause of obesity, or so they believed, but the evidence continued to accumulate just the same. Researchers had demonstrated that insulin seemed to have a dramatic effect on hunger, that insulin was the primary regulator of fat deposition in the adipose tissue, and that obese patients had chronically high levels of insulin. Other hormones, such as adrenaline, had been shown to increase the mobilization of fat from the fat cells. “It is probable that different concentrations of these hormones in blood are characteristic of different body types and fat contents,” Mayer wrote.