There are two habits that always seem to get sleep doctors riled up: using alcohol as a sleep aid and eating dinner late. If you want to dine with a doctor specializing in sleep, youd better ask them to meet you for the early-bird special because they certainly seem to collectively be against a late-night meal .

But what exactly constitutes late?

An early evening dinner isnt always realistic. Sometimes you have to make a dinner reservation past 8 p.m. to allow enough time to finish work, get ready and get to the restaurant. Maybe you work untraditional hours or your commute is long, making the idea of a 6 p.m. dinner completely laughable. And what about cultures where dinner is routinely eaten past 9 p.m., like in France or Spain?

We asked top sleep experts about the ideal time to eat dinner and what to do if you have to eat late but you still want to sleep well. Keep reading to see the verdict.

Why Sleep Doctors Recommend Eating Dinner Early

Different people have different ideas at what constitutes late (your grandparents may consider eating at 6:30 a late-night supper, for example). But sleep doctors define late in relation to your bedtime.

Ideally, there should be three hours between when you eat and when you go to bed, Dr. Catherine Darley , founder of The Institute of Naturopathic Sleep Medicine, told HuffPost. That means if you go to bed at 10 p.m., dinner after 7 p.m. is considered late.

There are good reasons why sleep doctors recommend eating dinner early in the evening. Everyone is different, but generally speaking, eating a heavy meal before bed can make it difficult to fall asleep and stay in a deep sleep. This is because it forces your body to digest when it should be resting, Dr. Hana Patel, a sleep expert for Time4Sleep , told HuffPost.

Patel explained that when the body is hard at work digesting your dinner while youre trying to sleep, it could cause some discomfort as well as prevent gut bacteria from resting. This, she said, interrupts the hormones that regulate the sleep-wake cycle. In the short term, this can lead to acid reflux . In the long term, it can lead to inflammation and increase the risk of obesity .

Darley added to this, saying that eating dinner late disrupts the bodys circadian rhythm, which is a 24-hour cycle that is part of the bodys internal clock. Since eating is a wakeful activity, eating late signals to the body that it should be awake, she said, explaining how a late-night meal can keep some people up at night.