Ask the RD: Is it Bad to Eat Your Calories at Night?

For the most part, you are probably better off eating during the day so your body has time to digest the food before you hit the sack.

Eating breakfast like a king, lunch like a prince and dinner like a pauper may actually have some truth behind it. Studies reveal that to reach the most optimal levels of fat burn, you need to go about 12 hours without eating. For most of us, that means ending our last meal by about 8 p.m., and holding off on breakfast until 8 a.m. or later.  

Here’s why: During the day, our brain and muscles need a certain number of calories for fuel — anything in excess of what’s directly needed for fuel gets stored as glycogen in the liver. At night, our bodies convert that glycogen into glucose and gradually release it into our bloodstream to keep blood sugar levels steady during sleep. Once the stored glycogen is gone, your liver begins to burn fat cells for energy.  

How does this translate to nocturnal eating? If you load most of your calories later in the day, you’re going to have to work a lot harder and longer to get through those glycogen stores. If you’re not eating until 9 or 10 p.m., then kicking off breakfast at 7 a.m., your body may never reach fat-burning mode.

Some people may also have trouble sleeping on a full stomach. A study from the Journal of Clinical Sleep Medicine found that eating more calories closer to bedtime may significantly disrupt healthy sleep patterns. Both volume and quality of food could be the reason you aren’t getting a solid night’s sleep — something that, over time, has been linked to greater risks for obesity and weight gain. The night time meal — trending even later now, due to longer work hours — is often delayed even more to fit in workouts, work functions and long commutes after work. Lying down to sleep on a full stomach makes reflux more likely … another sleep disrupter that affects as many as 1 in 5 Americans.

One of today’s top eating and fitness trends, however, is intermittent fasting. The basic premise is you eat within a certain window of time — usually restricted to about 8–10 hours. The remaining 14–16 hours of the day (including when you’re asleep) is void of all calories. In this case, if you’re prone to hold off on your first meal of the day until early afternoon, say noon or 1 p.m., then eating more calories later in the day may actually work in your favor — as long as you are able to go that long without replenishing. But this type of fasting behavior isn’t realistic for most people, and it’s often not sustainable.

If eating late is your best chance at getting a wholesome, quality meal for the day then stick with it. But if the “majority of your calories” translates to mindless, late-night snacking, poor quality food choices and bad sleeping habits, you may want to rethink your routine.

What we do know is this: Metabolism and blood sugar control are better in the morning than they are at night, so it makes sense to work most of your calories in earlier in the day. Your main focus needs to be on monitoring the quality of your entire day’s worth of calories, rather than when you eat it.