Just four days of junk food can impair memory and brain function: Study

New Delhi: Indulging in fatty fast foods like burgers and fries for just four days can disrupt the brain’s memory hub and trigger cognitive problems, according to a new study.

Researchers at the University of North Carolina (UNC), US, found that junk food can alter brain function almost immediately, even before weight gain or diabetes sets in. The study, published in the journal Neuron, highlights how Western-style diets rich in saturated fats pose risks to brain health.

The team discovered that a specific set of brain cells in the hippocampus, known as CCK interneurons, become overactive when exposed to a high-fat diet. This happens because the brain struggles to absorb glucose, leading to disrupted memory processing.

“We knew that diet and metabolism could affect brain health, but we didn't expect to find such a specific and vulnerable group of brain cells, CCK interneurons in the hippocampus, that were directly disrupted by short-term high-fat diet exposure,” said Juan Song, principal investigator and professor of pharmacology at UNC School of Medicine.

She added that what surprised researchers most was “how quickly these cells changed their activity in response to reduced glucose availability, and how this shift alone was enough to impair memory.”

Experiments on mice showed that memory problems appeared within four days of being placed on a high-fat diet. However, restoring glucose levels in the brain calmed the overactive neurons and reversed the memory issues.

The study suggests that interventions such as dietary changes, pharmacological treatments, or intermittent fasting could help protect against obesity-related neurodegeneration and preserve memory function.