No-no to the Yo-yo Effect

Want to lose weight and keep it off? Research suggests combining a protein-rich diet with circuit resistance exercise.


curveHow many Americans have struggled to lose weight, only to gain it back and then some? Blame their resting metabolism.

“When women typically try to lose weight, they’ll lose it, but about half or more of what they lose is muscle mass,” says Richard Kreider, director of the Exercise and Sport Nutrition Lab (ESNL) in the College of Education and Human Development.

“That muscle loss causes a reduction in their resting metabolism, which makes it easier for women to regain weight once they’ve lost it. It’s that yo-yo phenomenon.”

Through the Curves Women’s Health and Fitness Initiative, ESNL and Curves have paired to explore how diet and exercise may optimize weight loss and maintenance in women to improve their overall health. With headquarters in Waco, Texas, Curves is a weight loss and fitness franchise that focuses on female clients. It has more than 10,000 locations worldwide and more than four million members.

Diets rich in protein along with resistance training help build muscle, which boosts metabolism and burns more calories.

Over the last seven years, Kreider and his research team have performed 15 studies comparing different diet approaches coupled with exercise, including a higher-carbohydrate regimen, a higher-protein plan, and an American Heart Association–recommended diet. The team monitors study participants for changes in their resting metabolism, body composition, blood lipids, and other indicators.

“Much of what we’re trying to do in these studies is prevent the yo-yo phenomenon by promoting a better weight loss—mostly fat without much muscle mass loss—as well as trying to maintain or even increase resting metabolism, which makes it harder to regain the weight over time,” Kreider says.

“We have found that you can effectively promote weight loss without reducing resting energy expenditure, and that’s through a combination of circuit-type resistance training and maintaining a slightly higher-protein diet.”

Diets rich in protein help build muscle, as does resistance training (training with weights). Increased muscle mass boosts metabolism, which burns more calories. Kreider knows that choosing the right kind of exercise is important for women looking to lose weight and keep it off.

“Traditionally, when women tried to lose weight, they would go out and walk or do lots of aerobic exercise, so getting them to focus on circuit resistance training has been highly successful,” he says. “We’re changing the perception of exercise and weight loss in women.”

Women who have lost weight and want to maintain weight loss should continue to exercise. They should also monitor their weight.

“If they gain three pounds, they should reduce their caloric intake for a couple [of] days every month or so to burn off any small amount of weight before it has a chance to accumulate,” Kreider says.

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