A Canadian study has found a concerning association between heavy consumption of ultra processed foods and brain health. Researchers linked higher intake with an increased risk of stroke and future memory problems among adults who were considered healthy.

Researchers used magnetic resonance imaging scans to examine the brains of about 9,000 participants. Small areas of brain damage appeared more frequently among people who consumed large amounts of foods such as soft drinks, packaged snacks and sugary breakfast cereals.

Participants with the highest intake of ultra processed foods were 40% more likely to show these brain changes, Medical Xpress reported. The damage can go undetected because it does not produce obvious symptoms.

Although the changes may initially remain hidden, they can serve as early warning signs in the years before a stroke or memory problems begin. The findings therefore point to a possible connection that could emerge before people recognize changes in their health.

Russel J. de Souza, the study’s first author and an associate scientist at the Population Health Research Institute of McMaster University and Hamilton Health Sciences, described the results as unexpected.

"Usually, this kind of damage is associated with conditions we hear about and treat at a much older age," de Souza told Medical Xpress. He noted that the research involved "middle-aged Canadians who had no heart problems and reported no other health concerns."

The study was published in JAMA Network Open and included adults between 35 and 69 years old. In addition to the brain findings, participants who ate the most ultra processed foods carried more body fat and visceral fat.

Visceral fat is stored deep within the abdomen and is linked to health concerns including heart disease. The study also found that people who consumed more highly processed foods generally had more of this type of fat.

The association between ultra processed food consumption and brain damage was stronger among female participants. Women in the highest consumption group had nearly twice the likelihood of showing signs of brain damage compared with women in the lowest consumption group.

"Our findings suggest that the link between diet and brain health may be detectable before people experience noticeable problems with memory or thinking," said Sonia Anand, the study’s senior author and a senior scientist at the Population Health Research Institute.

Ultra processed foods are often appealing in taste, but they frequently lack important nutrients such as fiber, vitamins and minerals, according to the CDC. They can also contain high amounts of sodium, saturated fats and added sugars.

The CDC reported that ultra processed foods supplied an average of 55% of total daily calories among Americans ages one year and older between August 2021 and August 2023. The agency published those figures in August 2025.

Anand said the convenience and widespread availability of ultra processed foods could contribute to their high consumption. However, she warned that "diets high in these foods may be linked to brain changes that may lead to memory loss and stroke " in the future.

Among participants in the Canadian study, ultra processed foods accounted for an average of about 25% of daily food intake. Researchers also observed that consumption of nutrient dense foods declined as consumption of ultra processed foods increased.

Whole foods including fruits, vegetables and grains represented 41% of daily food intake among participants who ate the most ultra processed food. Those foods accounted for 68% of daily intake among participants who consumed the least.

The findings establish an association between eating ultra processed foods and indicators of changes within the brain, but they do not prove direct causation. Participants were evaluated only once and were not followed over time, preventing researchers from determining whether the foods directly caused the observed damage.

"We need longer-term studies that track people over time with repeated MRI scans to find out whether reducing ultra-processed food intake can slow or prevent these brain changes," de Souza said. He added that follow-up research is in the works.