People who dieted for two weeks, then paused cutting calories for two weeks - and repeated that pattern - lost more weight and fat than people who dieted continuously, according to a study published this week in the International Journal of Obesity.
The intermittent approach may fix what's always been a frustrating Catch-22 for dieters: To lose weight, you need to eat less, but when you eat less, your body responds by increasing appetite and burning fewer calories when you rest, hindering weight loss. It's a protective measure designed to conserve energy when your body thinks times are tough and you don't have enough food to eat. Think of it as a "famine reaction," said study coauthor Nuala Byrne, head of the School of Health Sciences at the University of Tasmania.
"Our body senses the change in energy intake... and brings out the artillery to defend our energy stores," Byrne told TODAY.
"This doesn't mean we can't be successful in long-term weight loss, we just need to have a better understanding of how the body works."
Hitting the pause button on your diet seems to reverse your body's protective response.
For the study, Australian researchers asked 51 obese men to follow one of two eating regimens. One group continuously followed a diet that cut daily calories by one-third for 16 weeks. The men in the second group ate the same diet for two weeks, but then took a break from it for two weeks. They repeated that pattern eight times.
The results? The men who took the breaks lost about 50 percent more weight than the others. They also shed more fat. Six months after the experiment, both groups regained some of the weight, but the men who took the diet breaks were still almost 18 pounds lighter on average than those who had dieted continuously.
So what's going on here? The diet "rest periods" may convince your body you're not starving after all, so there's no need to burn fewer calories or otherwise resort to the "famine reaction." Everything balances out.
If you want to try this plan, first figure out how many calories you need to eat to keep your weight stable, Byrne said. Then reduce that number by one-third, ensuring your diet is still nutritionally balanced, and stick to that limit for two weeks. Next: take a two-week break by increasing your calories back to the original number - minus 100 calories or so to account for your weight loss, Byrne advised. Then go back to dieting and repeat.
There a few important things to keep in mind. First, when it came time to take a diet break, the men in the second group didn't go on a two-week all-you-can-eat extravaganza. They ate the amount of calories designed to maintain their weight.
Second, not just any random "on-off" periods may do: The two-week intervals seem to be ideal based on previous studies on starvation, the study points out. A "cheat day" may undo the balance phase, Byrne said.
Finally, intermittent dieting is not the same as intermittent fasting, the researchers note. Intermittent dieting "creates distinct periods of weight loss and maintenance," while intermittent fasting - when you alternate days of severe food restriction with days of eating whatever you desire - works differently.
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