The best time of day to burn more calories

Listening to your body clock can help you manage your weight and reduce the risk of diseases like diabetes.

Whether we’re at work, rest or play, the time of day determines how many calories we burn.

And the number of calories we burn changes throughout the day – even when we’re resting – according to new research.

Our body burns 10 per cent more calories in the late afternoon and early evening than in the early morning, reveals the study by Brigham and Women’s Hospital and Harvard Medical School.

And it’s all to do with how our circadian rhythms – our internal body clock – affects our metabolism.

Best and worst times for calorie burning

The study found we burn the least amount of energy in the early hours just before waking, when our core body temperature is at its lowest.

We burn most energy about 12 hours later in the afternoon and early evening – when our body temperature rises.

“It is not only what we eat, but when we eat – and rest – that impacts how much energy we burn or store as fat,” notes Jeanne Duffy, of the division of sleep and circadian disorders at Brigham and Women’s Hospital.

How our body clock affects our weight

Professor John Hawley, director of Mary MacKillop Institute for Health Research at the Australian Catholic University, says we can use this knowledge to help manage our weight and blood glucose levels.

“There are circadian oscillations throughout the day and night – hormones and body temperature fluctuate,” says Prof Hawley.

“Daylight and exposure to the sun helps set circadian rhythms with the timing of meals also ‘fine tuning’ hormone release and blood glucose control.

“This helps explain the link between chronic metabolic diseases like obesity and type 2 diabetes and their higher incidence in shift workers.

“Their circadian biology is disrupted because they see little daylight and eat at different times of the day.”

How to eat in tune with your body clock

Most people eat over 14 or 15 hours per day – they may eat breakfast at 8am and are still grazing at 10pm, says Professor Hawley.

“But studies show that when we restrict our feeding time to eight to 10 hours a day, say from 10am to 6pm, even though we may not restrict our calorie input, we start to lose weight,” he says.

“Most people can easily eat for a shorter period of time and many subconsciously reduce the number of calories they eat by about 10 per cent because they can’t eat as much in that shorter timeframe.”

Restricting eating time also has a positive effect on blood glucose and the risk of type 2 diabetes.

If you eat late, your body has a higher glucose level throughout the night.

Eat dinner by 7pm and blood glucose returns to a healthy normal level before bedtime.

Top tips:

  • Restrict eating to eight to 10 hours a day, e.g. 10am to 6pm
  • Eat dinner by 7pm

Written by Sarah Marinos.