When you eat can be as important as what you eat

African american woman doing midnight snack at home. She eats a sandwich and looks for food into the refrigerator at night.

The balance between weight gain and weight loss is mostly determined by what you eat, how much you eat, and by how much exercise you fit in. But another important factor is often overlooked.

Published earlier this year in the open-access journal PLOS Biology, research conducted by Kevin Kelly, Owen McGuinness, Carl Johnson and colleagues of Vanderbilt University shows that it’s not just how many calories you eat, but when you eat them that will determine how well you burn the calories you just ingested.

They found that when the body chooses whether to burn fats or carbohydrates actually changes depending on the time of day or night.

People’s biological clock and sleep play important roles in how the food we eat is metabolised. This is because our body’s circadian rhythm has programmed the body to burn fat when sleeping, so when we skip breakfast and then snack at night, we delay burning the fat.

The researchers monitored the metabolism of mid-aged and older subjects, changing the times they fed the participants. Surprisingly, the daily timing of feeding, coupled with clock/sleep control of metabolism, flipped a switch in the subjects’ fat/carbohydrate preference.

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Those who took part in the late-evening snack session resulted in less fat burned when compared to the breakfast session.

A number of reasons have been made for the findings. When talking to Peter Janiszewski at Obesity Panacia – Dr. Satchidananda Panda, an Associate Professor in the Regulatory Biology Laboratory at the Salk Institute, said that “our body is designed to undergo overnight fasting. For millions of years humans ate only during the daytime. Only recently in the last 50 years our society began eating more at night, and during longer periods throughout the day.

“Much like our brain needs to rest at night, our data suggests that the stomach and the body’s digestive system need to rest from processing incoming fuel, otherwise we work our organs into a state of metabolic exhaustion.

“Imagine trying to perform major construction work on a busy highway in the middle of rush hour traffic? Our stomach and liver repairs itself every night, and consuming more food is similar to putting more cars on the road when repairs are being made. It causes a lot of chaos.

“Researchers may be overlooking the role that timing has on the body’s response to food.”

This study has pretty important implications for eating habits, suggesting that a regular fast between the evening meal and breakfast will optimise weight management. And that having breakfast each day really is one of the best ways to manage our weight.

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