Ultra-Processed Foods in the Daily Diet Silently Harm the Brain, Women at Greater Risk: Study

Ultra-processed foods in the daily diet can silently cause damage to the brain — such a warning has come from a new study by Canadian researchers. They obtained this picture by examining MRI scans of the brains of around 9,000 people.

The study found that those who eat larger amounts of ultra-processed foods — such as soft drinks, packaged snacks and sugary breakfast cereals — showed more small damaged areas in their brains.

Those who ate the most of these foods were 40 percent more likely to show such changes in their brains. What is worrying is that these changes usually create no clear symptoms, so the damage is not detected.

According to the researchers, these brain changes could be an early warning sign years before the onset of stroke or memory problems. That is, the process of damage may begin long before symptoms appear.

The study's first author, Russell J. de Souza, is an associate scientist at the Population Health Research Institute (PHRI) of McMaster University and Hamilton Health Sciences. He said this kind of damage is usually associated with diseases that are heard about and treated at much older ages.

Yet the participants in this study were middle-aged Canadians, aged between 35 and 69. They had no heart disease and had not reported any other health problems either. The researchers themselves were surprised to find such changes in the brains of healthy middle-aged people.

The study was published in the journal JAMA Network Open. It found that those who ate more ultra-processed foods also had more body fat and more visceral fat accumulated deep in the abdomen, which is associated with various health problems including heart disease.

But the most notable result was found in the case of women. The relationship between eating ultra-processed foods and brain damage was overall stronger among the women participants. The group of women who ate the most was nearly twice as likely to show signs of brain damage compared with the group who ate the least.

The study's senior author and PHRI senior scientist Sonia Anand said that from these results it is understood that the relationship between dietary habits and brain health may be identified before people feel noticeable problems with memory or thinking ability.

According to data from the US Centers for Disease Control and Prevention (CDC), ultra-processed foods generally contain low amounts of important nutrients such as fibre, vitamins and minerals, while containing high amounts of sodium, saturated fat and added sugar. According to a CDC report published in August 2025, an average of about 55 percent of the daily calories of Americans aged one year and older comes from ultra-processed foods.

For the participants in the study, ultra-processed foods made up on average about 25 percent of their daily diet. The researchers noticed that as the eating of ultra-processed foods increased, the eating of nutrient-rich foods decreased. In the group that ate the most processed food, 41 percent of the daily diet consisted of whole foods such as fruits, vegetables and grains, whereas in the group that ate the least, it was 68 percent.

In Sonia Anand's view, the use of ultra-processed foods may be higher because they are convenient and easily available. But a diet rich in such foods may be linked to brain changes that can lead to memory loss and stroke in the future.

However, the researchers warned that the participants were assessed only once and were not followed up afterwards. As a result, it cannot be said with certainty from this study that ultra-processed food is the direct cause of these brain changes. They believe long-term research, including repeated MRI scans, is needed to know whether reducing ultra-processed food slows or prevents these changes.