Ultra Processed Food and Colon Cancer: Only the Meat Stood Out

Jeff's Daily Pick. Ultra processed food gets blamed for everything. In 461,682 older Americans followed for nearly 19 years, it showed no overall link to colorectal cancer. Processed meat was the exception.

In the United States, researchers at the National Cancer Institute published an analysis in PLOS Medicine on October 15, 2026 asking whether ultra processed food raises the risk of colorectal cancer. They used the NIH-AARP Diet and Health Study, which enrolled adults aged 50 to 71 who filled in a detailed food questionnaire in 1995 and 1996. Ultra processed foods, group 4 of the Nova classification, already supply more than half of the calories eaten by U.S. adults.

The headline result

The analysis covered 461,682 people who were free of cancer at the start. Over a median follow up of 18.8 years, 10,075 developed colorectal adenocarcinoma. Median intake of ultra processed food was 43% of daily calories. People in the highest fifth of intake had the same risk as those in the lowest fifth (hazard ratio 0.97; 95% CI 0.91 to 1.03; p for trend 0.55), with no difference for the proximal colon, distal colon or rectum. Adjusting for overall diet quality or body mass index did not change the picture.

Why the label hides opposite effects

The category mixes foods that push in opposite directions. In this cohort, 82.8% of whole grain intake and 74.3% of processed meat intake came from ultra processed sources. Higher intake of industrial bread (hazard ratio 0.91), breakfast cereals (0.84) and frozen desserts and milk drinks (0.82) went with lower risk. Reconstituted meat and fish products went with higher risk (1.10; 95% CI 1.04 to 1.18). Each daily serving of meat from ultra processed sources carried an 8% higher risk, and meat from other sources 4%. Dairy, calcium, fiber and whole grain from ultra processed foods were all associated with lower risk.

One signal did favor less processing: replacing 10% of food grams from ultra processed sources with minimally processed food was associated with a 2% lower risk (hazard ratio 0.98; 95% CI 0.96 to 0.99). Earlier cohorts disagreed with each other. A 2022 BMJ analysis of three U.S. cohorts found higher risk in men but not women, and the European EPIC study later reported higher risk in women but not men.

The authors conclude that their findings support current advice for colorectal cancer prevention: eat whole grains, fiber, dairy and calcium, and avoid processed meat. The processing label alone did not sort the risky foods from the useful ones. Our piece on diet soda versus water looks at another product category where the label says less than the trial.