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On a Monday, this is MORNING EDITION, from NPR News. I'm David Greene.
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And I'm Linda Wertheimer.
Today, in Your Health, we're going to hear two stories about dieting. First, for people who are working hard to lose weight, actually shedding pounds is a great motivation to stay the course. But often, around four months into a regimen of diet and exercise, the pounds stop coming off.
NPR's Patti Neighmond has this report on the extremely frustrating diet plateau.
PATTI NEIGHMOND, BYLINE: For 62-year-old Susan Carriere, it all started quite a while ago when she had twins.
SUSAN CARRIERRE: I started battling weight, you know, up and down, and just didn't keep it off.
NEIGHMOND: Her weight went up and down for decades. At five-foot-six, when she hit 230 pounds, she decided to enroll in a weight-loss program. Over six months, she lost more than 50 pounds. She was ecstatic. But then things ground to a halt, and the scale, she says, got stuck at 181.
CARRIERRE: It wouldn't move. I was doing the same low-calorie, the same, you know, just about the same food every day.
NEIGHMOND: And the same walking program, but the stagnant scale went on for weeks.
CARRIERRE: You start questioning: Why am I doing it? If I'm not making any progress, you know, what's the point?
NEIGHMOND: Carriere's frustration is echoed by most people, says physiologist Eric Ravussin, a researcher at the Pennington Biomedical Research Center in Baton Rouge, where Carriere enrolled in the weight loss program. Just a 10-pound loss, he says, results in a smaller body that needs less energy to function.
ERIC RAVUSSIN: You are losing a backpack of 10 pounds that you don't have to carry around when you walk, when you go upstairs, or when you get off your chair.
NEIGHMOND: For example, your smaller body may now need 300 fewer calories a day. That means if you were on a 1,500-calorie-a-day diet, you'll now have to go on a 1,200-calorie-a-day diet in order to keep losing weight. On top of that, the body goes into starvation mode, resisting the weight loss, and begins to burn calories more slowly.
RAVUSSIN: And you have the perfect storm. You require less calories, but also you become more efficient. It's like, you know, going from an old Ford to a Prius with a more efficient engine.
NEIGHMOND: A more efficient engine isn't necessarily a bad thing. It means the body has adjusted to its new lower weight.
Dr. Lee Kaplan is an obesity specialist at Massachusetts General Hospital.
DR. LEE KAPLAN: Their diet plateau is their new set point. And so when you go to a healthier diet, your body says: Oh, this is good. Let's live at a lower body fat. Let's live at a lower set point.
NEIGHMOND: But to move below that lower set point, Kaplan says, you have to do something different.
KAPLAN: We try a diet. We try a different diet. We add exercise. We add a different kind of exercise. We encourage better sleep health. We encourage decreased stress.
NEIGHMOND: Inadequate sleep and too much stress often increase appetite. Different things work for different people. But pretty much everyone agrees that exercise - more of it, or adding a different type - works for most people. That's because healthy muscles burn more calories.
KAPLAN: If you're on the treadmill every day, you may burn a couple hundred calories a day from being on the treadmill. But you may burn six or 800 extra calories throughout the rest of the day when you're not on the treadmill, because your body's working better, because bodies with healthy muscles work better.
NEIGHMOND: For some people, simply persevering through the diet plateau works eventually. That's what happened to Susan Carriere. After four weeks of no weight loss, she got on the scale one morning and had dropped three pounds.
CARRIERRE: It's like the icing on the cake. I mean, all of a sudden, I feel like I rang the bell.
NEIGHMOND: But now that Carriere's body has adjusted to her smaller self, her weight loss will be slower than it was at the beginning of her diet. So she's taking Kaplan's advice and trying to do something different: a Zumba class.
CARRIERRE: It is the only thing that I have ever done that when you walk in, people are all smiling. And when you leave an hour later and you're sweating like an old dog, you're still smiling.
NEIGHMOND: And Carriere's hoping Zumba will help her shed that final 20 pounds.
Patti Neighmond, NPR News.