Why Time-Restricted Eating Can Support Sleep, According To Research
Chances are, you know someone who's had success with time-restricted eating (intermittent fasting) and is more than happy to tell you all about how it's improved their energy levels, digestion, hunger levels, and immune response. Its effect on sleep isn't talked about as much as these other benefits—but it could be just as noteworthy.
Why time-restricted eating can support sleep.
On a recent episode of the mindbodygreen podcast, mbg's vice president of scientific affairs Ashley Jordan Ferira, Ph.D., RDN, pointed listeners to reputable research1 finding that consuming meals within a consistent daily time window is associated with better sleep and overall quality of life. "Eating over a longer window and/or frequently changing that window is linked to exactly the opposite," Ferira explained. Eating during set times every day has also been shown to support healthy weight and insulin sensitivity2.
While some are able to get their feeding window down to as few as four hours a day, Ferira notes that sticking to a 12-hour window is more realistic for most people.
Time-restricted eating's impact on sleep likely has to do with the way it supports our circadian rhythm or internal clock. By doing activities like eating, exercising, and exposing ourselves to light at roughly the same times every day, we allow our body to slip into a routine. Once it does, it can become easier to fall asleep and wake up at the same time every day, which has a positive impact on sleep quality.
"From a chronobiology perspective, creating clearly delineated times when you eat, and when you fast, seems to be important to promote a healthy metabolism and good sleep. That means fewer meals, and during a shorter time window, for example, only between 10 a.m. and 8 p.m.," echoes neuroscientist and sleep expert Sofia Axelrod, Ph.D., of Kulala. She adds that eating full meals during set time periods can also help reduce grazing, or nibbling here and there throughout the day, an eating pattern that seems to negatively affect sleep3 timing and quality.
What to eat during your "feeding window."
As far as what to pile on your plate during this daily window, Peter Polos, M.D., Ph.D., FCCP, FAASM, sleep medicine specialist and sleep expert for Sleep Number, recommends steering clear of anything high in fat or refined carbs. "There is data to suggest4 diets high in carbohydrates contribute to drowsiness and can lead to fragmented sleep as the carbohydrates are metabolized. Avoidance of high-fat foods is also advised as they, too, can affect sleep quality," he tells mbg.
Instead, a review paper published earlier this year found that Mediterranean-inspired diets higher in protein, fiber, fruits, vegetables, and anti-inflammatory nutrients tend to be associated with better sleep quality.
Aim to enjoy most of your plant-heavy meals earlier in the day, as delayed eating might disrupt the circadian rhythm5. Experts agree that you should stop eating at the same time every night—preferably around three hours before bed—to give your body plenty of time to digest before sleep.
The bottom line.
Our bodies respond to a routine, so it makes sense that eating meals at the same time every day will benefit many facets of your health, including your sleep. There's research to suggest that restricting your eating times to 12 hours or less a day can keep your snoozing in tiptop shape. But if that isn't possible, at least try to keep mealtimes consistent and avoid grazing (especially during those tempting late-night hours).
Emma Loewe is the Sustainability Health Director at mindbodygreen and the author of Return to Nature: The New Science of How Natural Landscapes Restore Us. She is also the co-author of The Spirit Almanac: A Modern Guide To Ancient Self Care, which she wrote alongside Lindsay Kellner.
Emma received her B.A. in Environmental Science & Policy with a specialty in environmental communications from Duke University. In addition to penning over 1,000 mbg articles on topics from the water crisis in California to the rise of urban beekeeping, her work has appeared on Grist, Bloomberg News, Bustle, and Forbes. She's spoken about the intersection of self-care and sustainability on podcasts and live events alongside environmental thought leaders like Marci Zaroff, Gay Browne, and Summer Rayne Oakes.