- New research suggests the time of day may impact how many calories your body burns.
- You may burn more calories during the late afternoon than late at night.
- But, further research may be needed as the study was fairly small and performed under controlled conditions.
According to new research, your body may burn different amounts of calories depending on the time of day.
A small study that was recently published in “Current Biology” sought to determine if our circadian rhythm – the “internal clock” that controls when we feel sleepy, alert, or hungry – influences how many calories we burn throughout the day and night.
Researchers found that participants burned around 10% more calories in the late afternoon and evening than they did in the middle of the night. The difference amounted to around 130 extra calories burned.
In order to determine how many calories people burn at different points in their circadian cycle, participants wore sensors that tracked their core body temperature because a higher core body temperature reading means that a person is burning more calories.
Researchers also gradually shifted the sleeping and waking times of the participants to ensure the participants’ circadian rhythms weren’t influenced by external factors such as light exposure and social cues.
The study found that participants’ core body temperatures at rest were generally higher during the time period that corresponded to late afternoon. In contrast, their core body temperatures dipped during the late evening and early morning hours, around 12 hours afterward.
The findings suggest that our bodies burn the most calories performing basic functions in the late afternoon
In an interview with Time, the study’s co-author Dr. Jeanne Duffy, an associate professor of medicine at Harvard Medical School and a neuroscientist at Brigham and Women’s Hospital, stated that people may want to avoid eating during the calorie-burning lull that seems to occur late at night and early in the morning.
“We may be eating that breakfast not only at a time when our body might not be prepared to deal with it, but at a time when we need less energy to maintain our functions,” Duffy told Time. “Therefore, the same breakfast might result in extra stored calories, because we don’t need those to maintain our body functions.”
But, the findings are still preliminary
Although it may be tempting to try to use this information to hack your weight loss efforts, don’t reschedule all your fitness classes just yet. It’s important to note that the study only included seven participants and was performed under unique conditions.
Participants lived in a laboratory for 37 days and were not exposed to potential environmental disruptions such as clocks, windows, phones or the internet. Furthermore, the food intake and activity levels of the participants were closely monitored and controlled.
Although the findings of this study are still preliminary, researchers noted that the findings may be particularly relevant to ongoing scientific investigations into how working in shifts and working overnight impacts the health of employees.
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