If you have formed the habit of checking on every new diet that comes along, you will find that, mercifully, they all blur together, leaving you with only one definite piece of information: french-fried potatoes are out.

Jean Kerr (1922–2003) was an American humorist and playwright whose essays often drew on domestic life, social fashions, and the small humiliations of modern living. This quip comes from her mid‑century comic writing about the revolving door of health and diet advice—an era when “reducing” culture, magazine diet plans, and shifting nutritional orthodoxies became common features of middle-class life. Kerr’s humor typically treats such trends as simultaneously irresistible and absurd, emphasizing how quickly yesterday’s miracle regimen becomes today’s punchline. The line captures the weary consumer’s experience of trying to keep up with ever-changing dietary rules.

The joke hinges on the way diet culture produces more confusion than clarity: if you dutifully “check on every new diet,” the details dissolve into a blur. What remains is not wisdom but a single, punitive prohibition—“french-fried potatoes are out.” Kerr satirizes the moralizing tone of nutritional fads, where pleasure foods become the perennial scapegoat regardless of the diet’s supposed scientific rationale. The word “mercifully” is ironic: the only “mercy” is forgetting the endless rules, yet the survivor is still deprivation. The line critiques how self-improvement regimes can reduce life to anxious restriction rather than genuine health.