Stunkard became a leading authority in the study of behavioral therapy for obesity, which can be defined as a system of behavioral techniques by which obese patients might come to endure semi-starvation, while avoiding the explicit judgment that they achieved their obesity because they lacked willpower or had a defect of character. For instance, they eat too fast, or they are overly responsive to the external cues of their environment that tell them to eat, while being unresponsive to the internal cues of satiation, as one popular theory of the early 1970s had it. “Fat Americans: They Don’t Know When They’re Hungry, They Don’t Know When They’re Full,” as a New York Times headline suggested in 1974. By that time, obesity, like anorexia, was categorized as an eating disorder, and the field of obesity therapy had become a subdiscipline of psychiatry and psychology. All these behavioral therapies, call them what you may, were in fact aimed at correcting failures of will. Every attempt to treat obesity by inducing the obese to eat less or exercise more is a behavioral treatment of obesity, and implies a behavioral-psychological cause of the condition.

Even if we accept that obese individuals are possessed of a defective character, then we’re still left in the dark. Why doesn’t the same defect—“the combination of weak will and a pleasure seeking outlook upon life,” said Louis Newburgh—cause obesity in everyone? “It exists in many non-obese individuals as well,” observed Hugo Rony; “in some of these it leads to chronic alcoholism, or drug addiction, others may become gamblers, playboys, prostitutes, petty criminals, etc. Evidently, such mental makeup, in itself, is not conducive to obesity. Those who do become obese apparently have something additional to and independent from this mental makeup: an intrinsic tendency to obesity.”

If we can believe that people become obese because they simply ignored the fact that they were getting increasingly fatter, year in and year out, with the passive accumulation of excess calories, and that by the time they noticed it was either too late to do anything about it or they really didn’t care (despite claims they might make to the contrary); if we can believe that obese individuals fail to survive indefinitely on semi-starvation diets because they are gluttonously unwilling to forgo temptation and so prefer, consciously or unconsciously, obesity to a life of moderation, then, as Stunkard observed in 1959, the matter is settled. Our job is done. But, of course, it isn’t.