If you eat chips from a bag, drink soda from a bottle, or rely regularly on packaged breakfast cereals, frozen entrees, or fast food, new research suggests the cumulative effect on your brain may be more significant than most Americans realize. Ultra-processed foods — industrially manufactured food products containing little or no whole food, typically loaded with flavor enhancers, stabilizers, colorings, and preservatives — now account for more than 53 percent of total calories consumed by American adults and 62 percent of children's calories. A converging body of 2025 and 2026 research is establishing that this dietary pattern has measurable consequences for the brain, cognition, and long-term dementia risk.
A study published in the American Journal of Public Health examined data from thousands of older Americans tracked through the Health and Retirement Study — testing memory and cognitive function every two years — and found that participants with the highest UPF consumption faced significantly higher risks of both cognitive impairment and dementia. Among all UPF subcategories, processed meat showed the strongest association with cognitive risk. A 2026 systematic review of 14 studies found that 78.5 percent reported significant associations between higher UPF consumption and poorer cognitive outcomes, including deficits in memory, executive function, and global cognition.
