Among Bishop’s many claims, his insistence that smoking causes cancer proved the most prescient. During the 1940s and 1950s, when Bishop wrote his pamphlets, few serious studies on smoking and cancer existed, and cigarette ads regularly appeared in the Journal of the American Medical Association. Nonetheless, Bishop latched onto those few studies to support his prescription for a healthier lifestyle and constantly reminded his readers of the cancer connection. Not until a 1952 article in Reader’s Digest did public opinion begin to shift against tobacco companies, and only in 1953 did the American Medical Association ban tobacco ads in its publications. Bishop trumpeted this victory. In 1964, three years after Bishop’s death, the Surgeon General’s Advisory Committee on Smoking and Health released a report concluding that smokers were much more likely to develop lung cancer than nonsmokers.
Not all of Bishop’s claims have proven as accurate; he unequivocally used any existing evidence to support his conclusions regardless of scientific merit. In this leaflet the cartoon asserts that coffee can cause heart disease (recent studies have suggested otherwise) and that soda can cause polio (likely a result of the 1951 book Diet Prevents Polio, in which Benjamin Sandler erroneously claimed that sugar increases the risk of polio). Many of Bishop’s messages were useful; many others were misleading.