"We present evidence that eating UPFs increases several nutrient and metabolic markers of disease and is associated with structural brain changes in areas that regulate eating behavior," the study authors wrote.

Key Brain Changes Identified

The research, recently published in Nature, found that people who consumed more UPFs showed measurable differences in brain areas involved in feeding behavior, emotion, and motivation.

Higher UPF intake was linked to increased thickness in the bilateral lateral occipital cortex—a brain region crucial for visual object recognition and processing shapes. This finding suggests changes in how the brain processes visual food cues.

"Our findings indicate that a high consumption of ultra-processed foods is associated with structural changes in brain regions regulating eating behaviour, such as the hypothalamus, amygdala and right nucleus accumbens. This may lead to a cycle of overeating," Arsène Kanyamibwa, the study's first author and doctoral researcher at the University of Helsinki, said in a press statement.

The study also uncovered a potential biological mechanism behind these brain changes. Researchers found that increased UPF intake was associated with higher levels of systemic inflammation and risky metabolic markers in the blood, including C-reactive protein (CRP), an indicator of inflammation; triglycerides; and glycated hemoglobin (HbA1c). High levels of CRP, triglycerides, and HbA1c are often considered concerning indicators of potential health issues.

Unsurprising Findings, Expert Says

The findings "don't surprise me one bit," said Dr. Joseph Mercola, a board-certified family physician and author of "Your Guide to Cellular Health," who was not involved in the study.

He pointed to previous research showing that just five days of eating ultra-processed foods can "short-circuit" insulin signaling in the brain. This matters because insulin isn't only a blood sugar hormone, he noted. "It's literally the delivery service that shuttles glucose, your cells' preferred fuel, to where it's needed most—your brain."