Watching out what you eat is just half of the battle. According to a study published in the American Journal of Clinical Nutrition, when you eat also plays a role in weight gain. In particular, late-night consumption of food – especially before going to sleep – has an important role in the composition of the body.

While that may be the case, according to corresponding author Dr. Andrew McHill of the Oregon Institute of Occupational Health Sciences, feeling hungry is normal for most people. “Our internal biological clock actually increases feelings of perceived hunger in the evening independent of any behaviors,” he explained.

The study also focused on the effects of eating at a later circadian time, compared with clock hours. There have been multiple studies that demonstrate eating at a later clock hour increases the risk of metabolic conditions such as obesity; however, not much is known about the relationship between circadian time, that is, the standard notation of an organism’s subjective time in relation to its circadian cycle, food intake, and body composition. (Related: 5 Habits That Ruin Your Sleep.)

The researchers involved 110 participants, aged between 18–22 years, for the 30-day cross-sectional study. During this time, researchers evaluated sleep and circadian behaviors as they went throughout their daily activities. To monitor their food intake, the team used a time-stamped-picture mobile phone application – which was conducted as the participants went about their daily routines. They also recorded body composition and the timing of melatonin release during in-laboratory tests.

They found that individuals that had a high body fat consumed most of their calories an hour before the onset of melatonin, which signals the start of the body’s biological night. Leaner men, on the other hand, only consumed significantly less during those times. This, despite both groups having similar clock hours of food consumption.

The body, in particular, is made up of its own biological clock – which has its own day and night function. When melatonin is released into the body, it takes it as the start of its night function, or “circadian evening,” as researchers put it.

The circadian clock is also what regulates metabolism, explained McHill. If a person eats closer to his bedtime, his biological clock doesn’t function the same way as it does during its biological day, where it boosts metabolism. This means that the food will be stored as excess calories in fat, instead of burning it off.

Further studies also revealed that food intake, in relation to the onset of melatonin, is linked to body fat percentage and body mass index (BMI). However, the same results were not present between “clock hour of food intake, caloric amount, meal macronutrient composition, activity or exercise level, or sleep duration and either of these body composition measures.”

“These results provide evidence that the consumption of food during the circadian evening and/or night, independent of more traditional risk factors such as amount or content of food intake and activity level, plays an important role in body composition,” the team concluded in their study.

To learn when a person’s biological night kicks in, McHill says that melatonin levels start to rise at least two hours before he usually goes to sleep. That translates to – if a person usually sleeps at 1:00 a.m., he should try to stop eating by 11:00 p.m. Likewise, people who sleep earlier should also try to cut back on snacking earlier as well.

Learn more about ways to cut back on midnight snacks on Slender.news.

Sources include:

Academic.OUP.com

RunnersWorld.com

Pubs.NIAAA.NIH.gov