Interestingly, the protective effects were maintained even when the mice were given "cheat days," when time-restricted feeding was temporarily interrupted by allowing the mice free access to food during the weekends, a protocol that would seem particularly relevant to humans. And when obese mice who had been eating freely were moved to a restricted schedule they lost 5% of their body weight even though they were eating the same number of calories as before. The results of two studies publishing online December 2 in the Cell Press journal Cell Metabolism suggest that this time-restricted eating affects the balance of bacteria found in the gut.
– Instead of counting calories next time you want to lose weight, try keeping an eye on the clock. US researchers at the Salk Institute have found that restricting eating to an 8-to-12-hour window each day can help the body burn fat instead of storing it, the Telegraph reports. Mice whose eating was restricted "had a number of protective and therapeutic health benefits compared with animals allowed to eat the same number of calories from the same food source at any time," says the lead researcher in a press release. Mice who only had access to food for up to 12 hours per day gained less weight than mice who could eat whenever they wanted—regardless of the number of calories consumed or whether the diet was high in fat or sugar. And mice that gained weight by eating on an unrestricted schedule were able to reverse the effect by restricting eating to a nine-hour window: Even if they ate the same number of calories as before, they stopped gaining weight and dropped 5% of their body weight in days, Discovery News reports; by the end of the 38-week study, they weighed 25% less than mice who kept eating on an unrestricted schedule. Researchers also found that brief breaks in the routine (a "cheat day," perhaps, or a weekend during which you don't restrict your eating times) had little negative effect. And in addition to preventing obesity, the overnight fasting for 12 hours or more also had positive effects on blood sugar and cholesterol, as well as reversing the effects of diabetes, the BBC reports. (Another reason to skip that midnight snack: Late-night eating can hurt your memory.)