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Early birds, rejoice!

Reviewed by Dietitian Karen Ansel, M.S., RDN

Key Points

• The ideal time to eat dinner for cognitive health is three hours before bedtime.
• This timing may promote brain health by improving sleep, blood sugar and oxygen delivery.
• Eating fatty fish, mushrooms, nuts and berries may also support cognitive health.

Have you ever wondered how some people can possibly eat dinner at 5 p.m.? Turns out, they may be on to something. Experts say that eating an early dinner can actually improve your cognitive health. While you may not need to sign up for the early bird special, eating dinner about three hours before bedtime may do good things for your brain health over both the short and the long term.

But before we dive into the details, you may be wondering, what exactly is cognitive health, and why does it matter? Cognitive health refers to how well we think, learn and remember. “Cognitive health isn’t just about preventing dementia later in life—it affects our productivity, emotional resilience and quality of life right now,” says Jessica Cording, M.S., RD, CDN.

So, yes, improving it can have big benefits. But if eating dinner three hours before bed sounds extreme, keep reading to learn why it’s so effective, plus additional dinnertime strategies for better cognitive health.

Why 3 Hours Before Bed Is the Best Time

You’ll Probably Sleep Better

“We know late meals, especially heavy ones, are known sleep disruptors,” says Maggie Moon, M.S., RD. Think back to the last time you ate a rich, creamy meal like fettuccine Alfredo or butter chicken close to bedtime. Chances are, it sat uncomfortably in your belly, making it harder to fall asleep.

But the effects of late-night meals go beyond just feeling full and disturbing your sleep quality. They also influence how well your brain functions. Sleep is like a deep cleanse for your brain, clearing away the day’s toxins, including amyloid-beta, a protein that forms pathogenic plaques linked to Alzheimer’s disease, says Moon. When sleep is poor or disrupted, like when you eat too close to bedtime, this cleanup process may be less effective, negatively impacting short-term and long-term cognitive health.

Conversely, sound sleep improves both memory and cognitive performance the next day, notes Moon. That’s why it’s so important to treat both dinnertime and bedtime as appointments you can’t skip, even if you’re cramming for a test or preparing for a big presentation the next day.

It May Keep Blood Sugar Steady

Fluctuations in blood sugar can affect attention, memory and performance. Eating dinner earlier may help keep your blood sugar steadier, which matters for your brain’s functioning.

Moon points to research that found that when people ate dinner at 6 p.m., they had more stable blood sugar levels and greater fat burning the next day, versus when they ate dinner at 9 p.m.

There’s another, less direct way that eating earlier helps manage blood sugar, and that’s by regulating your body’s internal clock (aka circadian rhythm). Here’s why: Your body is wired to use glucose more efficiently during the day. Trouble is, eating later at night confuses your body’s internal clock. “Limiting night-time eating has been shown to help maintain glucose rhythms and circadian alignment, both of which are tied to brain function and attentional performance,” explains Cording.

It May Deliver More Oxygen to Your Brain

Your brain needs a constant supply of oxygen to function, and when you eat may influence how much oxygen it receives. “Eating early appears to enhance how much oxygen is available for the brain to use for energy production, which may be why a combination of eating early and physical activity [has been linked] to improved cognitive function,” says Moon. She points to one study of women who followed a time-restricted eating pattern and engaged in physical activity. Some of the women were instructed to eat earlier in the day, while others were told to eat later. Those who ate earlier had higher blood oxygen levels and better alertness.

Other Dinner Strategies to Improve Cognitive Health

When it comes to cognitive health, it’s not just when you eat dinner that matters —it’s also what you eat. These foods and habits can support better brain function.

• Eat More Fatty Fish: Fatty fish like salmon and mackerel are rich in omega-3 fats, which support brain and heart health and may improve sleep quality and sleep duration, says Cording.
• Add Mushrooms to Your Plate: Mushrooms are rich in ergothioneine, an amino acid with neuroprotective properties. Research found that people who eat more mushrooms perform better on cognitive tests and may have a lower risk of cognitive decline.
• Sprinkle on Nuts: Did you know pistachios and walnuts contain the sleep-regulating hormone melatonin? Since better sleep can help support cognitive health, sprinkle them on salads, grain bowls or roasted veggies at dinner.
• Eat Raspberries: Raspberries have been shown to enhance memory and learning in older adults. Enjoy them after dinner in a yogurt bowl or dipped in dark chocolate.
• Sip Tart Cherry Juice: Tart cherry juice also naturally contains melatonin and has been shown to improve sleep quality and duration. Tart cherry juice can also help reduce inflammation, which is important for a healthy brain.
• Cook Dinner: Cooking is an advanced cognitive task, says Moon: “Cooking involves high-level thinking, including planning, multitasking, real-time decision-making and more.” Rather than ordering out, whip up a healthy dinner that supports brain health.
• Eat with Others: “Share a meal with someone to build cognitive reserve and give the brain a social workout,” suggests Moon. “Listening, interpreting facial expressions and responding all engage the brain. Plus, socializing reduces isolation and loneliness, a risk factor for cognitive decline.”

Our Expert Take

Eating dinner earlier is an easy way to support your cognitive health. How early is early enough? Dietitians say the best time to eat dinner for better cognitive health is about three hours before bedtime. This strategic timing may help you sleep better, keep your blood sugar levels stable and enhance oxygen delivery to your brain—all of which are important for cognitive health. Other dinnertime strategies that can support cognitive health include adding fatty fish, mushrooms, raspberries and nuts to your meal. While you’re at it, why not invite a friend or loved one to dinner? You’ll enjoy your meal more and keep your brain sharp while you’re at it.