Want to burn more fat? Fast 18 hours per day

Friends enjoying lunch (iStock)

A new preliminary study reveals a way to burn more fat—but you have to be willing to restrict all your daily eating to a 6-hour window. Researchers found that participants who took in all their daily calories between 8am and 2pm burned 6% more fat than those who spread out their calorie intake from 8am to 8pm, LiveScience reports.

The two groups ate the same meals, the Sydney Morning Herald reports. "Your body's fat-burning ability peaks after you've been fasting for 12 to 14 hours," the lead author of the study explains.

That's because, for the first 12 hours of fasting, your body burns glycogen (a molecule that stores sugar). After 12 hours, it starts to burn fat stores.

However, researchers don't consider the 6% difference statistically significant, which is why the results are considered preliminary until further research is done. The study also found that those who ate during a 6-hour window experienced more stable hunger levels than those in the 12-hour group.

Participants rated their hunger from 0 to 100; average hunger levels were the same, but the 6-hour group experienced fewer hunger swings—their hunger levels did not vary as much (12 fewer points of variance) as the 12-hour group's levels.

The lead researcher says it's not clear why, but it could be due to the fact that those in the 12-hour group had only consumed two-thirds of their daily intake earlier in the day, prior to dinner, and "that might set you up more for binges or unhealthy eating than if you've already eaten all of your food for the day." The researchers caution that children and pregnant women must avoid fasting, and anyone with a chronic health condition must ask a doctor first.

(The new dieting trend: souping.)

This article originally appeared on Newser: Want to Burn More Fat? Fast 18 Hours a Day