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Do Diets Actually Work?

MINNEAPOLIS (WCCO) -- Every year, a top New Year's resolution is to lose weight. Any at given time, an estimated 45 million Americans say they're on a diet.

But, do diets work? Good Question.

"People can lose weight on a diet, but usually that weight loss is not sustained," says Megan Baumler, director of the didactic program in dietetics at St. Catherine University.

There are hundreds of diets –- ketogenic, Atkins, Whole 30, Weight Watchers, low-carb, just to name a few –- and studies have shown they can help people lose weight and lower blood pressure in the short-term. It's the long-term where people have a hard time keeping the weight off.

One analysis of weight loss studies found, on average, people regained more than half their lost weight within two years. With five years, 80% of people put the weight back on.

"It's physiological, it's not because of some lack of willpower," says Dr. Iesha Galloway-Gilliam, co-director of Hennepin Healthcare's Comprehensive Weight Management Center. "That's why it's so difficult to maintain these dietary patterns."

Dr. Galloway-Gilliam says when people restrict calories, hunger hormones ramp up to drive cravings and the same amount of food doesn't make you feel as full anymore. At the same time, people's metabolism -– or calories burned at rest –- drops.

Traci Mann, director of the University of Minnesota's Health and Eating Lab, adds another reason for why it's hard to people to stick to a diet: psychology. When people reduce their calorie intake, they can develop an obsession with food, making it harder to get it out of their minds and making them more likely to eat.

"If you think of these three things, none of them make it impossible to keep dieting, but they all make it a lot harder," she says.

Her research found, on average, dieters regain all but one pound of the weight they lost over two to four years.

Dr. Galloway-Gilliam says managing weight is a lifelong process. She points to four categories to think about when it comes to successful weight loss: nutrition, exercise, sleep and stress.

First, she says people should minimize eating ultra-refined processed foods and reduce sugar intake.

Second, while she points out exercise is helpful, it's not the most potent intervention. She says people should exercise because of the health benefits, but have an expectation that is appropriate.

Third, she says adults need seven to eight hours of restorative sleep.

Fourth, managing stress can better help people change their behaviors like emotional eating.

She also recommends anyone trying to manage their weight have a strong support network and come up with an individualized plan that's sustainable for them.

"I tell my patients: we're now friends for life," she says.

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