Book Review

Fat: Fighting the Obesity Epidemic

N Engl J Med 2001; 344:940-941March 22, 2001

Article

Fat: Fighting the Obesity Epidemic
By Robert Pool. 304 pp., illustrated. New York, Oxford University Press, 2001. $27.50. ISBN: 0-19-511853-7

The mystery: people in industrialized societies are growing ever fatter, and attempts at sustainable weight loss often prove fruitless. The sleuths: scientists who, over the course of a century, arrive at some understanding of the complex interactions among genes, environment, and behavior that establish a person's body-weight “set point.” The set point, moved upward by the successes of industrialization, appears recalcitrant to long-term change. But is it?

Robert Pool weaves a wonderful and balanced tale, linking the important 20th-century discoveries that led to the idea of the set point and our current understanding of the regulation of body weight. This is no simple reiteration of well-known history. Pool adds rich new details to the epidemiologic, psychological, and molecular discoveries behind one of the most interesting stories of modern biologic science. The author integrates this complex information in an entertaining manner, and he advances his own views about future research and policy. This book is a must for anyone interested in the history of science, public health, or the related epidemics of obesity and type 2 diabetes mellitus.

The odyssey meanders through the developments of the past century to arrive at our current view of the regulation of body weight. Pool uses the story of a patient in a Turkish study to introduce this view. Patient 24, a hyperphagic, morbidly obese man, was unusual among the obese subjects enrolled in the study. At age 22, he was prepubertal, had little facial or pubic hair, and had hypogonadism. Pool links the condition of Patient 24 to that of the obese (ob) mouse that was identified in 1950 at the Jackson Laboratory in Maine and was shown in 1994 to harbor the mutation that causes a failure of leptin synthesis. The cause of obesity in Patient 24 was not a lack of willpower, notes Pool, but rather the “near-absolute power this genetic mutation seem[s] to hold over [its] victims.”

This story is not, however, solely about the genetics of body-weight regulation. The author traces, with ample and interesting detail, the psychoanalytic theories that the influential Hilde Bruch advanced in the early 1960s and Stanley Schachter's imaginative “externality” theory that followed. A later section examines Stunkard's classic Midtown Manhattan Study, which revealed for the first time the close link between socioeconomic status and body weight. The behavior-therapy approach initiated in 1967 by psychologist Richard Stuart is woven together with the studies of Pavlov, Skinner, and Schachter. Moreover, rather than relegate these studies to mere historical footnotes, Pool returns to them toward the end of the book as he develops his own view of a somewhat plastic set point that might permit the lowering of body weight.

In support of this view, Pool does trace advances in biology as well as psychology. The story of the book's central theory of the brain's regulation of body weight begins with the 1840 observation of a woman who grew progressively fatter in the last year of her life and was found on autopsy to have a large pituitary tumor. Then came Froehlich's 1901 report of obesity and hypogonadism caused by a pituitary tumor and the observation in 1939 that ablation of the hypothalamus in rats caused obesity. In 1973, Coleman's seminal experiment in ob mice showed that there must be a circulating satiety factor produced by fat cells. Additional support for the regulatory control of body weight was provided by the studies of overfeeding and underfeeding in humans that were conducted by Leibel and Hirsch. The molecular door was finally opened in 1994, when Friedman and his colleagues discovered that leptin, a previously unrecognized hormone secreted by fat cells, is absent in the ob mouse. As Pool traces these advances, he also gives fascinating insights into the investigators' personalities and working environments.

Anyone, whether clinician or patient, who is interested in the pharmacologic management of obesity should read the chapter entitled “One Pill Makes You Larger, and the Other Makes You Small.” Pool shows, with strong historical support, that greater drug-induced weight loss is usually accompanied by greater side effects and can be fatal. However, he does not close the door on drug treatment for obesity, but, rather, reviews some encouraging ongoing research on such medications. This engaging book tells a fascinating story that extends far beyond the information available in journal articles and asks how we, as an advanced society, can fight the obesity epidemic.

Steven B. Heymsfield, M.D.
Columbia University College of Physicians and Surgeons, New York, NY 10025