Could losing weight really be as simple as shifting the hours we eat? While it’s too early to say if it’s true for humans, new research from the Salk Institute is impressive, demonstrating that when mice are kept from eating for stretches of between 9 and 15 hours, they lose weight, even when consuming the same number of calories as mice that eat whenever they feel like it. Even better? Within two weeks of the 38-week study, the rodents significantly improved their cholesterol and blood glucose levels, and overweight mice lost 5% of their body weight.
“It’s very difficult to make human recommendations at this point,” Amir Zarrinpar, M.D., a post-doctoral fellow at Salk, told Life Reimagined. “But the big take-away here, from a human perspective, is that metabolism is complicated. It’s not simply a matter of calories in and calories out. At certain times of day, the machinery that is in place to process energy works differently.”
This study adds credence to the concept that the body may need to fast for longer periods in order to maintain healthy weights. While all the mice were fed the same number of calories, their diets were different (high-fat, a mixture of fat and sucrose, or all sucrose). All the time-restricted mice did better than mice who were allowed to eat whenever they wanted, but the effects were strongest in mice with high-fat diets, and 9, 12 and 15-hour fasts.
Even better? Some of those mice were given weekends off, to mimic the way people change their eating schedule when not at work. At the end of eight weeks, even the weekends-off mice had more lean muscle and lower cholesterol levels.
"We were really happy to see that the timing restriction worked no matter what the diet was, in terms of fat versus sugar, and with the fact that it worked over the weekend,” says the Amandine Chaix, also a postdoctoral researcher, and the study’s lead author. “It was very forgiving. Our studies suggest that fasting seems to have a beneficial effect on metabolism.” While human trials are the next step, the researchers say it can’t hurt to experiment now. If you normally eat breakfast at 7 a.m., for example, why not finish dinner by 7 p.m., and banish night-time snacking for two weeks?
You’ve got nothing to lose but some weight.