Even though successes of preventive medicine in the control of infectious disease have lent support to the proverbial worth of "an ounce of prevention," there was always some doubt whether, in fact, an ounce vis-à-vis a pound truly expresses the right proportion of expended effort to attained results. These doubts increased when preventive medicine began to encroach on cherished habits. To the habitual smoker, the case for abjuring cigarettes in order to fend off lung cancer could hardly be presented in terms of ounces and pounds. Nor could current dietary constraints, advocated for prevention of atherosclerotic heart disease, be made readily acceptable to the lover of good food by simply quoting the proverb. In terms of personal comfort the cost of prevention is going up in an inflationary spiral.
The cost is also going up in terms of money, energy, and time, with medicine's increasing involvement in early disease detection.
A POUND OF PREVENTION. JAMA. 1966;198(4):480. doi:10.1001/jama.1966.03110170192034