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Archive for Sunday, February 6, 2005

Measuring metabolism

Technology helps consumers figure amount of calories needed

February 6, 2005

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— You know those people who can eat anything they want whenever they want and seemingly not gain an ounce?

They probably have their resting metabolic rate to thank.

Resting metabolic rate represents the calories your body needs to maintain vital functions, such as heart rate, breathing and brain function. The higher the number, the more you can eat without packing on the pounds.

Thanks to technology, dietitians increasingly are using hand-held calorimeters that came onto the market several years ago to measure people's resting metabolic rate and develop individualized diet and exercise plans.

"It gives people a more accurate picture of what their calorie needs actually are and how much activity they need to do," said Mary McArthur, community nutrition educator and dietitian at Medina (Ohio) General Hospital.

After all, experts estimate resting metabolic rate accounts for about 75 percent of all the calories you use each day.

Medina General is among the hospitals offering resting metabolic rate measurements with a machine known as MedGem. (Lawrence Memorial Hospital does not have a MedGem).

The cost for a measurement varies, depending on where it's done and what services are included. But patients usually pay from $30 to $100 for a measurement and, in some cases, comprehensive nutrition counseling.

To find out their resting metabolic rate using MedGem, people plug their noses and breath through the machine's mouthpiece for five minutes to 10 minutes while they rest.

The machine measures the amount of oxygen consumed, which it uses to determine resting metabolic rate.

To ensure an accurate reading, you must avoid eating, drinking, exercising, caffeine and decongestants for at least four hours before testing.

Once the machine gives a reading, a dietitian uses a formula based on how active you are to determine the total amount of calories used each day.

"In order to lose weight, it all goes back to calories in and calories out," said Maxine Smith, clinical dietitian for Summa Health System in Akron, which uses MedGem.

To lose a pound a week, for example, you need to shed 500 calories a day. Want to lose two pounds a week? Then you need to cut calories by 1,000 a day.







There are some things you can do to boost your resting metabolic rate.For starters, include strength-training exercises that build muscle mass in your weight-loss plans, said Karen Bangert, a personal trainer at the Akron (Ohio) General Lifestyles Health and Wellness Center.The reason: Muscles burn up more calories than fatty tissue, even when the body is resting."Muscle is metabolic tissue," she said. "There is not a whole lot of value to fatty tissue. If you can increase your lean muscle mass and decrease the fatty tissue on your body, you are then going to be able to boost the resting metabolic rate."Another way to improve your resting metabolic rate is to eat smaller, balanced meals more frequently rather than a couple of big meals, Bangert said."In order to make sure we have a good maintenance of resting metabolic rate, we want to make sure people have good food frequency, so they're eating every three to 3 1/2 hours," she said. "You don't want to go long periods of time without food because this, again, does impact metabolic rate."

Crash-diet problems

But be warned: nutrition experts say it's difficult to meet nutritional needs if daily calories dip below 1,200.

People who go on crash diets and slash too many calories too soon are ultimately setting themselves up for failure, McArthur said.

When calorie intake dips below the amount needed to maintain vital body functions, survival mode kicks in. Your body adapts and learns to make do with less energy.

Ultimately, your resting metabolic rate drops. And when you quit that hard-to-maintain crash diet, guess what? You'll now gain weight even faster if you return to eating the same foods you did before the diet made your resting metabolic rate lower.

Adjusting

Another problem: People who lose weight too quickly also tend to lose muscle mass, said Dr. Troy M. Smurawa, a sports medicine physician at Akron Children's Hospital.

"The faster you lose it also means you're going to lose more lean body mass," he said. "If you lose lean mass, your resting metabolic rate will drop and, therefore, your overall metabolic rate will drop."

Joyce Lagios knows firsthand the ups and downs of dieting.

"There isn't one I haven't tried," she said.

Nothing seemed to work until last year, she said, when she got involved with a program at Summa Health System geared to make sure women have healthy hearts.

As part of the program, she met with Smith, who tracked her resting metabolic rate to help her adjust her diet and exercise plans.

After noticing Lagios' resting metabolic rate dropped while she dieted, Smith recommended she increase her exercise routine from once to three times a week.

Lagios said she's lost 62 pounds in the past year and plans to lose 50 more.

Though it's possible to find formulas on the Internet that use age, weight and height to determine resting metabolic rate, people should beware that these tools are accurate for only about 20 percent of the population, Smith said.

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