This Is The Time Of Day When You Burn The Most Calories

Not all calories are equal and it turns out the time of day you tuck into dinner can affect the amount you burn – or store as fat. That’s according to a preliminary study published in the journal Current Biology last week.

Researchers at Brigham and Women’s Hospital discovered that when at rest, humans burn calories 10 percent faster in the late afternoon than late at night. All in all, this could add up to 130 extra calories and that’s without lifting a finger. 

To find this out, the scientists recruited a small team of volunteers aged 38 to 69 and put them in a lab, where they were kept devoid of phones, the Internet, clocks, and even windows for 37 days. This meant they had absolutely no way of telling the time. Participants were also kept on a strict timetable, which involved having their food, activity, and sleep schedules carefully regulated by the researchers.

Every day, the researchers moved the day’s schedule back four hours to throw the participants’ internal body clocks out of whack, forcing their circadian rhythms – bodily processes that follow a 24-hour cycle – to tick along guided only by internal factors. This, the researchers say, is equivalent to traveling west through four time zones every single day for three weeks. 

“Because they were doing the equivalent of circling the globe every week, their body’s internal clock could not keep up, and so it oscillated at its own pace,” co-author Jeanne Duffy, an associate professor of medicine at Harvard Medical School, said in a statement. 

“This allowed us to measure metabolic rate at all different biological times of day.”

During the experiment, the volunteers wore body temperature sensors. A high core temperature showed the person was burning more calories. A low core temperature showed the opposite. When the data came in, the researchers found that resting energy expenditure appeared to be at its lowest during the circadian phase corresponding to late nighttime and early morning and at its highest during the circadian phase corresponding to the late afternoon/early evening period, 12 hours later. 

So, what does this mean exactly?