A new study from researchers at the UNC School of Medicine has found that eating junk food doesn’t just affect your waistline—it can scramble your memory in as little as four days.
Scientists discovered that a diet high in saturated fats, like cheeseburgers and fries, overstimulates certain brain cells in the hippocampus, the brain’s memory hub. These cells, called CCK interneurons, become overactive when the brain can’t get enough glucose, or sugar, from food. This disruption makes it harder for the brain to process and store memories.
Dr. Juan Song, the lead researcher, said what surprised the team most was “how quickly these cells changed their activity” and how even short-term junk food exposure caused problems.
The findings, published in the journal Neuron, show that diet affects the brain almost immediately—well before signs like weight gain or diabetes appear. The study also suggests that simple changes, such as intermittent fasting or switching to healthier foods, can calm overactive neurons and restore memory function.
This research adds to growing evidence that poor diets increase the risk of long-term cognitive problems like dementia and Alzheimer’s. “What we eat can rapidly affect brain health,” Dr. Song said, noting that early interventions could protect memory and lower risks linked to obesity.
The message is clear: what’s on your plate today can shape how sharp your mind feels tomorrow. Choosing healthier meals—even just most of the time—may be one of the best ways to keep your memory strong for years to come.
