By almost every measure we should care about – longevity, healthspan, and quality of life – preventing colon cancer matters. Yet the recently released 2025 Dietary Guidelines for Americans largely ignore dietary patterns that scientific evidence has long suggested are protective. A new study in AJCN strengthens our understanding of this mistake.

The Consortium of Metabolomic Studies

The study is a harmonized analysis of nearly a million men and women from the Consortium of Metabolomics Studies. It confirms what decades of nutritional epidemiology have long suggested. Holistic dietary patterns centered on low-insulin-stimulating, anti-inflammatory food choices predict a substantially lower risk of colorectal cancer. It is a massive and rigorous pooled analysis. Participants in the healthiest quintiles of insulinemic, inflammatory, and overall diet quality indices had 15 to 20% lower colorectal cancer risk than those in the least healthy quintiles.

Well-Understood and Healthy Dietary Patterns

These aren’t abstract scores. They reflect diets rich in vegetables, fruits, whole grains, legumes, nuts, and seeds. These diets are low in refined carbohydrates, added sugars, and processed foods that can promote systemic inflammation. A systematic review used in the guideline advisory committee process found evidence that dietary patterns with these features, including low red and processed meat intake, predict lower colon cancer risk. But, of course, HHS Secretary RFK Jr. discarded all that work.

A Bias to Promote Red Meat

The secretary made no secret from the beginning that he favored red meat and beef fat. This was a political statement. So his guidance promotes red meat and says nothing about processed meats. It flies in the face of credible nutrition science that suggests processed meats are carcinogenic and that red meat – in excess – probably is carcinogenic, too. Both red and processed meats have robust epidemiologic associations for colorectal cancer.

We need not eliminate these meats from our diets. But promoting more consumption of them is irresponsible.

Ambiguity That Fails Americans

It’s not enough to say “eat less sugar” or “avoid ultra-processed foods.” For colon cancer prevention we need clear emphasis on healthy dietary patterns – plant-forward, anti-inflammatory, and low in harmful meat exposures – not ambiguous allowances for liberal red meat consumption. The science is clear. Dietary guidelines should follow it.

Click here for the study in AJCN, here and here for further perspective.

Still Life with Ham, painting by Meijer de Haan / WikiArt