Scientists have identified a unique population of brain cells responsible for forming memories of meals, capturing both what was eaten and when it occurred. The research, published in Nature Communications, may help explain why individuals with memory difficulties are more prone to overeating and why forgetting a recent meal can heighten hunger and contribute to unhealthy eating behaviors.

As eating takes place, neurons in a part of the brain called the ventral hippocampus become active, creating what the researchers describe as “meal engrams.” These are specialized memory traces that record details of eating experiences. Although engrams have long been known to store general memories and experiences, this study is the first to reveal a set of engrams specifically linked to meals.

“An engram is the physical trace that a memory leaves behind in the brain,” said Scott Kanoski, professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences and corresponding author of the study. “Meal engrams function like sophisticated biological databases that store multiple types of information such as where you were eating, as well as the time that you ate.”

Distracted eating implications
The discovery has immediate relevance for understanding human eating disorders. Patients with memory impairments, such as those with dementia or brain injuries that affect memory formation, may often consume multiple meals in quick succession because they cannot remember eating.

Furthermore, distracted eating — such as mindlessly snacking while watching television or scrolling on a phone — may impair meal memories and contribute to overconsumption.

Based on the experiment’s findings, meal engrams are formed during brief pauses between bites when the brain of laboratory rats naturally survey the eating environment. These moments of awareness allow specialized hippocampal neurons to integrate multiple streams of information.