"This allows adequate time for digestion, thereby reducing any possible disruption to sleep caused by poor digestion," Polos says of the three-hour window. This is especially important when eating protein-rich or fatty foods, like meat or fish, which tend to take a bit longer to digest.
Eating too early in the evening won't do your sleep any favors either, though, since going to bed hungry can lead to blood sugar dips that wake you up in the middle of the night. Wrapping up right around three hours before bed seems to be the sweet spot for most people.
However, if you can't nail this timing night after night, neuroscientist and sleep expert Sofia Axelrod, Ph.D. of Kulala says not to stress. From her perspective, it's just as important (if not more so) to eat dinner at roughly the same time every night; whenever that may be. "It matters more that your eating times remain as constant as possible from day to day than whether they are one hour before bedtime or three hours," she tells mbg.
That's because meals are one of the many daily activities that help regulate the timing of our circadian rhythms, which dictate our sleep-wake cycles. "If you always eat at the same time," Axelrod explains, "your body learns to prepare the digestive tract (e.g. by producing digestive enzymes) to optimally digest the food you eat." Along with being strategic about your light exposure during the day, eating at the same time during the night can help keep your sleep schedule ticking smoothly and dependably.