Ultra-Processed Foods Linked to Poorer Focus and Slower Mental Processing in Adults
A study of more than 2,100 adults found that eating ultra-processed foods was associated with poorer focus and slower mental processing, even among people who otherwise maintained a healthy diet. Researchers said the findings suggest these foods affect brain function independently of overall diet quality.
A study of more than 2,100 adults found that people who ate more ultra-processed foods scored lower on tests of focus and mental processing speed, even when researchers accounted for overall diet quality.
The findings, published in June 2026, suggest that ultra-processed foods, which include packaged snacks, fast food, sugary drinks, and ready-to-eat meals, may affect brain function through mechanisms that go beyond simple calorie intake or nutritional deficiency.
Participants completed dietary surveys and cognitive tests measuring attention, processing speed, and working memory. Those who consumed the most ultra-processed foods showed measurably slower reaction times and more difficulty sustaining attention compared to those who ate the least.
The effect held even among participants who otherwise ate plenty of fruits, vegetables, and whole grains, suggesting that the harm from ultra-processed foods is not simply offset by eating well in other areas.
Researchers said the findings are consistent with earlier animal studies showing that certain food additives and emulsifiers common in ultra-processed products can disrupt gut bacteria and trigger low-grade inflammation, which in turn affects brain function.
The study adds to a growing body of evidence linking ultra-processed food consumption to a range of health problems, including obesity, type 2 diabetes, cardiovascular disease, and depression.
Experts said the findings underscore the importance of food labeling reforms that would help consumers identify ultra-processed products. Several countries, including Brazil and France, have already implemented such systems.
