A study in Italy showed that people who eat a lot of pizza are less likely to get colon cancer. And another study says masturbation reduces risk of prostate cancer. It's what I've always said: diet and exercise.

In this joke, Leno riffs on the way health news headlines can be cherry-picked into simplistic “life hacks.” He juxtaposes two sensationalized study claims—pizza lowering colon-cancer risk and masturbation lowering prostate-cancer risk—then delivers the punchline by reframing them as “diet and exercise.” The humor comes from the deliberate category error: masturbation is recast as “exercise,” and pizza as “diet,” mocking both the elasticity of wellness advice and the audience’s appetite for reassuring conclusions. Beneath the gag is a satirical point about how scientific findings are often reduced to comforting, self-serving slogans.