Just 4 Days of Junk Food Can Harm Memory, Study Finds

New Delhi: If you're a fan of cheeseburgers, fries, and other fast food, here's a wake-up call: a new study has found that just four days of eating a high-fat, junk food diet can begin to disrupt memory and brain function.

Researchers from the University of North Carolina (UNC) in the US have discovered that fatty foods can reprogram key brain cells in the hippocampus, the brain’s memory centre, even before you gain weight or develop diabetes.

Published in the journal Neuron, the study reveals that a special group of brain cells called CCK interneurons becomes overactive after a short period on a high-fat diet. This happens because the brain struggles to take in glucose (sugar) — its primary energy source — when exposed to too much saturated fat.

This sudden shift in brain cell activity disrupts how memories are formed and processed.

“We knew that diet and metabolism affect brain health,” said Professor Juan Song, lead researcher at UNC’s School of Medicine. “But we didn’t expect such a fast and specific reaction from CCK interneurons after just a few days of a high-fat diet.”

The team studied mice placed on a diet mimicking Western fast food. After only four days, the mice showed changes in brain activity and memory problems.

A key protein, PKM2, which helps brain cells manage energy, was also found to play a role in this process.

The good news? Researchers found that restoring glucose levels in the brain helped calm the overactive neurons and reversed the memory issues. Simple dietary changes, including intermittent fasting, were enough to reset brain activity and improve memory.

This research shows how quickly unhealthy eating can impact brain health and highlights the importance of early lifestyle interventions — such as balanced diets or fasting-to prevent long-term damage linked to obesity.

So next time you reach for fast food, remember: your memory might suffer more quickly than you think.