Packaged bread, breakfast cereals and ready-made meals are often grouped together as unhealthy ultra-processed foods. However, new research suggests that judging everything by its level of processing may overlook important nutritional differences.

A large American study involving more than 460,000 adults found no overall association between ultra-processed food consumption and colorectal cancer incidence. Instead, researchers discovered that individual food categories showed different relationships with the disease.

Published in PLOS Medicine on 15 October 2026, the findings offer a more nuanced perspective on one of today's most widely debated dietary concerns.

What The Researchers Discovered

Scientists led by Erikka Loftfield at the US National Cancer Institute analysed information from 461,682 adults aged 50–71 when they entered a major health study in 1995 and 1996.

Participants completed dietary questionnaires describing their usual eating habits. Researchers then examined cancer diagnoses over a median follow-up period of 18.8 years.

Contrary to expectations, eating larger quantities of ultra-processed foods was not associated with a higher overall incidence of colorectal cancer.

However, examining specific food groups revealed important differences that were hidden within the broader category.

Why Food Categories Matter

Ultra-processed foods include an enormous variety of products, from packaged wholemeal bread and fortified cereals to processed meat and confectionery.

Although these products share certain manufacturing characteristics, their nutritional qualities can differ substantially.

The researchers found that higher consumption of ultra-processed whole grains and dairy products was associated with lower colorectal cancer incidence.

Foods containing fibre and calcium showed similar favourable associations.

By contrast, greater consumption of processed meat was linked to higher cancer incidence.

These findings suggest that nutritional composition may provide more useful information than processing classification alone.

Could Simple Changes Help?

Researchers also investigated the potential association between replacing ultra-processed foods with minimally processed alternatives.

Their analysis suggested that substituting 10% of ultra-processed food intake by weight was associated with a 2% lower incidence of colorectal cancer.

Although modest, this finding highlights how dietary patterns may influence long-term health.

However, the results do not establish that replacing a particular product will directly prevent cancer.

The type of food being replaced, and the nutritional quality of its alternative, remain important considerations.

Why The Study Has Limitations

Despite its impressive size, the research cannot establish cause and effect.

Participants reported their dietary habits only once, meaning researchers could not fully account for changes over subsequent decades.

Food manufacturing also evolved considerably during the study period, potentially affecting how accurately early questionnaires represented later consumption.

Most participants were older white Americans, so the findings may not apply equally to younger or more diverse populations.

These limitations make further investigation necessary.

What Should We Eat Instead?

The findings support established dietary guidance emphasising whole grains, fibre-rich foods and balanced nutrition.

Practical choices include oats, beans, vegetables, fruit and suitable dairy products.

Rather than automatically rejecting every packaged food, consumers can examine ingredient lists, fibre content and overall nutritional value.

Reducing processed meat consumption remains consistent with recommendations for lowering colorectal cancer risk.

A More Balanced Perspective

The study challenges the idea that every ultra-processed product carries identical health risks. Its findings suggest that what foods contain may matter as much as how they are manufactured.

For everyday eating, focusing on nutritional quality and overall dietary balance remains a sensible approach.