Smoking helps you lose weight — one lung at a time!

Framed as a punchline, the line satirizes the idea—common in advertising and popular belief—that smoking can be a tool for weight control. The twist (“one lung at a time”) converts “losing weight” into a grim kind of loss: the deterioration of vital organs through smoking-related disease. Attributed to Alfred E. Neuman, MAD magazine’s fictional mascot, it fits MAD’s long-running style of mocking consumer culture and public-health evasions by pushing a slogan to an absurdly literal, bodily conclusion. The humor depends on shock and inversion: a supposed benefit is revealed as self-destruction.