How often do you feel a rumbling in your stomach or get an urge to raid the fridge before bed? It used to be common for nutritionists to recommend a bowl of cottage cheese and a slice of toast to promote better sleep. But now, many experts advise against eating snacks late at night. Some even recommend prolonging the time between dinner and breakfast to as long as 16 hours.
To complicate matters, many people make their unhealthiest food choices late at night—pulling out the tub of ice cream or the bag of chips after the kids are tucked in. Others eat at night because of boredom or habit rather than real hunger.
The decision of whether or not to return to the kitchen after hours should not be taken lightly. Our actions become our habits, and our habits become our health. In this article, we look at whether eating before bed is good or bad, how many hours we need to fast each night, and what happens inside our bodies during the overnight fast.
Is Eating Before Bed Good or Bad?
The journal Nutrients published a complete review of the science on nighttime eating in 2015. The biggest takeaway from this article was that nighttime eating is good for some people and bad for others.
Nighttime eating was found to be a good thing for people who were particularly active or exercised in the evening. Also, bedtime snacks that were nutritious and small (about 150 calories) were found to support muscle protein synthesis overnight. The article also mentioned that people with type I diabetes or other health conditions might require a bedtime snack.
On the other hand, eating before bed might have harmful effects in people who are sedentary, overweight, or obese. In these people, a late-night snack might worsen insulin resistance, glucose regulation, or other aspects of metabolism.
How Many Hours Do I Need to Fast Overnight?
Since the time that the article was published in Nutrients, more research has emerged on the benefits of an extended overnight fast. In August of 2016, JAMA Oncology published a study of overnight fasting in women with early-stage breast cancer.
After following 2413 women for more than seven years, researchers found that a 13-hour overnight fast was the magic number. Women who fasted less than 13 hours overnight had a 36% higher risk of breast cancer recurrence than women who fasted 13 hours or more each night.
Because of the results of this study, many nutritionists recommend that people aim for a minimum of 13 hours between the time they eat at night and the time they eat the next morning.
What Happens During the Overnight Fast?
Fasting no doubt influences cellular and metabolic function. Animal studies have taught us most of what we know about the body’s response to fasting, but human studies are beginning to confirm these mechanisms. Studies suggest that fasting supports healthy blood sugar, blood pressure, insulin sensitivity, body fat, lipid levels, and inflammation. Some go a step further to say that it also supports healthy aging.
The overnight fast also gives the digestive system a rest. It allows the migrating motor complex (MMC) to cleanse the bowels. This period of rest from eating is helpful for everyone, but especially for those who need additional digestive support.
What’s the Bottom Line?
Fasting has been practiced in a variety of ways for thousands of years. Recent studies suggest that you might attain some of the benefits of fasting by the simple act of extending the overnight fast to 13 hours or longer. This can easily be achieved by finishing dinner by 6 pm and eating breakfast after 7 am.
Most people don’t need to eat a snack before bed, but every person is unique. The answer to whether or not you should eat a bedtime snack depends on your metabolism and lifestyle. Listen to your body and its needs. And if you want a bite to eat before bed, keep it light and keep it healthy.
Sarah Cook, ND
Instructor, Nutrition Therapy Institute