One Day, Not Three: What the Latest Colonoscopy Diet Guidelines Actually Say

The American Cancer Society suggests up to five days of low-fiber eating before a colonoscopy. Europe’s leading endoscopy society has recommended one day since 2019, and 2025 U.S. guidelines now say the same for most low-risk patients. Patients are left with conflicting instructions, even though studies show shorter diets are easier to tolerate. This post breaks down what the guidelines say, why prep sheets still vary, who may still need a longer diet, and how Zera Medical is rethinking where the prep step happens.