Nonetheless, Mayer claimed that the study confirmed the findings of his rat experiment. He based his conclusion exclusively on the relative girth of thirteen stallholders and eight supervisors. These men weighed, respectively, fifty to sixty pounds and thirty to forty pounds more than the clerks who worked for them, and yet, according to Mayer’s data, consumed the same amount of calories. Mayer implied that they added this extra weight because they were somehow even less active than those employees whose jobs entailed sitting all day, but he had no evidence for it. It’s also possible that their relative wealth introduced other dietary factors that could have explained the dramatic differences in weight. Either way, as John Garrow noted, these findings would never be replicated, which is why such authorities as the Institute of Medicine of the National Academies of Science still cite Mayer’s study today as the only evidence for the proposition that “too little” exercise can disrupt the mechanisms that normally regulate food intake.

Mayer’s advocacy of exercise for weight control did not go unchallenged. After his 1965 New York Times Magazine article, entitled “The Best Diet Is Exercise,” physicians working with obese patients wrote to the newspaper saying that Mayer’s faith in exercise was unreasonable and flouted common sense. “As much as Dr. Mayer minimizes the thirst and appetite increases after exercise, my patients all seem to be thirstier after tennis and find it difficult to stick to plain water,” wrote Morton Glenn of New York University College of Medicine; “and who hasn’t heard someone say: ‘This walk all the way home sure gave me an appetite!’ Exercise can and does increase thirst and appetite, in most persons, in most situations, and most people respond to these sensations accordingly!”

Despite these commonsensical objections, Mayer’s hypothesis won out. It helped that Mayer—like Ancel Keys and Dennis Burkitt—perceived the process of convincing the public and the medical-research community to be akin to a crusade. This served to absolve him, apparently, of the obligation to remain strictly accurate about what the research, including his own, had or had not demonstrated. In the popular press, Mayer would unleash his less scientific impulses. He wrote about the “false idea which continues to have broad and pernicious acceptance” that exercise would increase appetite, and he insisted that the “facts overwhelmingly demonstrate” that this was “not necessarily” the case.