You’re pulling super late hours at work. You’re out drinking with your buddies. You’re spending long stretches of time traveling or commuting. Your grueling workout has tapped all the fuel in your tank. All these scenarios have one thing in common. (No, this isn’t an SAT question.) Each one has you raiding the fridge at midnight to quell the grumbling state of your stomach.
We’ve all succumbed to the cravings, but a new University of California study finds the late-night behavior could be affecting us beyond disrupting our sleep or packing on the pounds (as if that isn’t bad enough). Researchers found that midnight snacks can wreak havoc on the hippocampus, the part of our brains where memories are formed.
In the study, which was conducted on mice, researchers allowed some mice to eat at night—which is part of their normal eating pattern—and prompted others to feed during the daytime. All the mice were kept in cages with wire grids that restricted their access to food, and given a six-hour window—depending on the day or night schedule—in which they could eat. The researchers monitored their nocturnal tendencies, sleep-wake behavior, and their contextual fear conditioning (whether they remembered getting the shock—and by consequence showed signs of fear of it happening again) by administering a mild shock to the mice after they ate.
The mice who had eaten during hours they normally slept showed a natural fear response, which indicated that they remembered the shock, while the mice who had eaten during their typical waking hours were less likely to react. In other words, the first group of mice basically “forgot” they had been shocked the last time they ate at that hour. Turns out, digesting food when the mice were meant to be asleep affected their long-term memory and mental function. The researchers theorize it’s because these mice had reduced levels of a protein called CREB, which is essential for the body’s internal clock and the brain’s ability to form memories.
So how does it influence us?
Lead study author Dawn Loh told the Daily Mail: “We have provided the first evidence that taking regular meals at the wrong time of day has far-reaching effects for learning and memory. Since many people find themselves working or playing during times when they’d normally be asleep, it is important to know that this could dull some of the functions of the brain.”
However, more studies need to be done in order to truly see how eating when we typically should be sleeping can impact our health—aside from raising blood sugar levels (enhancing the risk of diabetes and heart problems), which we already know. Take note if you’re a chronic night owl or frequent late-night fridge-raider.