Did you know that your metabolism burns more calories at certain times of day, even if you’re doing nothing at all?

It turns out that during the afternoon and early evening, your body could be burning a whopping 10% more calories than at other times of day, no matter what you’re getting up to.

The news comes from a study published in Current Biology and is based on an experiment involving seven people. The participants stayed in an isolated laboratory with no windows, clocks, phones or internet – meaning they had no sense of time.

Over the course of three weeks, they were assigned times to go to bed and wake up, which were adjusted throughout the experiment to stop their bodies settling into a rhythm.

The experimenters were then able to measure their metabolic rate throughout the day, to find the body’s natural patterns.

‘The fact that doing the same thing at one time of day burned so many more calories than doing the same thing at a different time of day surprised us,’ says lead author Kirsi-Marja Zitting of the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital and Harvard Medical School, both in Boston, MA.

The team now plans to examine how your appetite can change depending on the time of day.

How can I speed up my metabolism?

While we all have our own natural metabolic rates, you may find that eating your biggest meal at lunch rather than dinner time may speed up weight loss, as most people burn more calories in the afternoon and early evening.

‘It is not only what we eat, but when we eat — and rest — that impacts how much energy we burn or store as fat. Regularity of habits, such as eating and sleeping, is very important to overall health,’ says Jeanne Duffy from the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital.