Intermittent Fasting Helps You Sleep Better: True Or False?

Sleep-promoting foods run the gamut, and experts have their own top-tier lists—but they all agree, on some level, that colorful, magnesium-rich plants are a fabulous choice. See, magnesium is a mineral that's important for lots of functions in the body, including sleep1, and many people skimp on it2 (i.e., almost half the nation).* "Nuts, seeds, whole grains, leafy greens, legumes—these are magnesium-dense foods that should go into your [grocery] cart," our director of scientific affairs and in-house nutritionist, Ashley Jordan Ferira, Ph.D., RDN, told us on the mindbodygreen podcast. 

We're certainly not going to knock a bedtime snack, especially one that includes the essential mineral. But there's emerging evidence that fasting, or restricting your eating to a smaller number of hours, could improve sleep. Here, Ferira breaks down a recent study she read in the journal Endocrine Reviews that outlines a link between time-restricted eating (a type of intermittent fasting) and better sleep.

How time-restricted eating impacts sleep

Here's the gist: According to Ferira, consuming meals in consistent daily windows of less than 12 hours "is linked to less obesity, better metabolic health, and—guess what!— better sleep." On the flip side, they found that "eating over a longer window and/or frequently changing that window is linked to exactly the opposite," she says. 

The logic makes sense, as if you have an eating window of more than 12 hours, chances are you're eating later in the night—and if that meal is super hearty or excessively sweet or spicy, it might mess with your slumber. "Our largest meals should not ever be close to bedtime," Ferira adds, and plenty of research3 has associated late dinners or eating more calories late in the evening and short sleep duration (less than five hours). Of course, a growling, empty stomach can keep you up at night as well, so you do want to listen to your natural body cues if you are hungry at night—just opt for one of these foods that keep blood sugar levels steady and provide relaxing benefits. 

But let's circle back to that 12 hours or less eating window: We know that there are many alterations to intermittent fasting, and some plans have more flexibility than others. The study Ferira mentions isn't so strict about the exact schedule so long as it's less than 12 hours of eating. No matter the specific plan you follow, try to make sure it's consistent every day—as the study notes, frequently changing the window of eating can have the opposite effect on sleep and overall health. You shouldn't stay married to a plan that is unhelpful or unhealthy for you, but once you find one that works, do your best to stay consistent. 

The takeaway

Time-restricted eating comes with a number of health benefits, and you can add better sleep to that list, as long as your window is less than 12 hours and you keep up with it daily. Eat in a sleep-smart way throughout the day (with high-quality sources of protein and magnesium-rich plants) and you should be golden. Oh, and if you need a little more support? Feel free to check out our favorite sleep supplements that support a healthy circadian rhythm.*

If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.

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