This may be the best news to ever break in the world of dieting: Taking half the month off from a strict nutrition plan could actually help you lose more weight—and keep it off—compared to restricting your calories full time, according to a study in the International Journal for Obesity.
The only catch: It’ll take more time.
In the study, two groups of men followed a diet in which they cut their calories by a third. One group dieted in the manner we all know and hate: continuously, for 16 weeks. The other group cut back for two weeks, then broke from the diet for two weeks, eating to keep their weight stable rather than at a deficit. They repeated this two-weeks-on, two-weeks-off strategy for 30 weeks total.
In the end, both groups dieted for four months, but the latter spread it out over seven or eight months. And though it took more time, they ended up losing 11 more pounds than people who just cut calories for four months straight. Most important, though, this intermittent diet group was able to keep the weight off in the long run. Six months after the end of their respective dieting cycles, the intermittent diet group had maintained an average loss of 17lbs more than the regular dieting group six months after.
“Part of the difficulty in losing weight and maintaining weight loss by lifestyle changes such as dieting is that the body responds to calorie restriction through a series of compensatory changes in its metabolic processes,” explains lead study author Nuala Byrne, Ph.D., professor of health sciences at the University of Tasmania. “Cutting back on calories triggers a powerful reaction by our body’s metabolism.”
Quick refresher here: Your body stores excess calories in fat cells for a rainy day (or, for our caveman selves, for when we’re trapped, destitute, and without food for days on end). Feeding it less calories means you have to tap into those reserves to reach the same daily quota, and your body essentially brings out the artillery to defend those emergency stores, Byrne explains. That defense comes in the form of reducing your resting metabolic rate—the energy you expend doing nothing but sitting still—and increasing your appetite to motivate you to find food, plus some changes in your hormone network and nervous system.
“These adaptations collectively slow weight loss and can promote weight gain—what we call the body’s ‘famine reaction,’” Byrne explains.
That’s why trying to diet over a long period is so tough: The famine reaction acts like friction on your weight-loss process. Byrne’s study suggests that taking time away from calorie restriction can circumvent the famine response—so you’ll lose weight without convincing your body it’s starving.
Interestingly, other studies have found that the more traditional forms of intermittent dieting—wherein you restrict calories or, more commonly, fast entirely for specific hours or specific days, and then eat as you want otherwise—don’t help you lose much more weight than continuous dieting.
“[Intermittent fasting] works off the principle that people won’t make up all the deficit from the fasting days in their feeding days, so there will be an overall calorie deficit over time,” Byrne explains. “Our approach ensures that balance is actually achieved.” Of course, some people will just go hog wild once they can eat again—but that’s up to you.
That being said, some people do lose weight using traditional intermittent fasting, just as they do with continuous dieting. If you find either of these easy and effective, go for it, Byrne adds.
But if fasting or being on a diet 24/7 drives you insane, this two-weeks-on, two-weeks-off approach may serve you better. Taking breaks from dieting may also help you develop more sustainable habits, Byrne adds. The only catch: You definitely have to take the marathon mindset to weight loss, since eight months is a long time when your brain is ready to see results before beach season.