- The Washington Times - Tuesday, January 29, 2002

Aging has definite pluses and minuses: We tend to gain both wisdom and weight. Doctors hope Americans can use some of the wisdom to fight the weight gain.As people enter middle age, the body's metabolism slows gradually. Older adults find that foods they could devour in their 20s without putting on an ounce of weight cause them to swell considerably.
"One of the main reasons our metabolism drops is that we lose muscle mass as we get older," says Dr. Stephen Clement, an endocrinologist at Georgetown University Hospital.
Metabolism is the work the body does including thinking, breathing and exercising that requires the energy that food, oxygen and fluids provide. The rate at which the body uses energy is known as the metabolic rate. This rate slows with age as the body loses muscle.
Every pound of muscle you lose can decrease the number of calories you burn per day by as many as 30. That means if you lose 10 pounds of muscle mass over many years, your metabolism could slow down by as many as 300 calories a day.
"People can lose as much as 10 percent to 20 percent of their muscle mass over several years," says Dr. Jules Hirsch, an endocrinologist and professor emeritus at Rockefeller University in New York City. Dr. Hirsch has studied metabolism for about 35 years.
"Sometimes [people] stay the same weight because they have replaced the muscle mass with fat. … Or they might gain weight," he says.
Naturally, adults want to boost metabolism. As a society, we often look for quick fixes over-the-counter pills that promise to put our metabolism in high gear.
Some of those pills can be effective, but they often have unwanted side effects, and nutritionists and doctors caution against this method of losing weight.
"Many of them are massive diuretics. So you'll lose weight because you're dehydrated," says Lisa Snyder, a licensed dietician at Georgetown University Hospital.
Others contain caffeine, which speeds up the metabolism and heart rate, which can be damaging to the heart in the long run.
"The correct way to increase your metabolism is not through chemical intervention. It isn't safe," Dr. Hirsch says.
Maybe pharmaceutical researchers will develop a safe metabolic booster such as a hormone that will stimulate muscle growth but that could take decades, he says.
• • •
However, some researchers claim that adults need help to lose weight. More than half the population is overweight and at higher risk for diabetes and heart disease than if they were at their best weight, according to the Centers for Disease Control and Prevention.
"I don't think we should write off supplements because we have had some awful ones in the past," says Dr. Harry Preuss, a professor of physiology at Georgetown University Medical Center and a long-time researcher on nutrition and supplements. "What we need to do is more research on these products."
Ephedra, an herb that has been used in China for thousands of years to treat asthma and hay fever, for example, helps boost metabolism, and Dr. Preuss says he has used it effectively himself.
"We have to realize that everything is not going to work on everyone," he says. "We don't have those demands on pharmaceuticals."
The U.S. Food and Drug Administration is considering taking ephedra off the market because consumers have reported they become dizzy, experience changes in heart rate and blood pressure and get headaches from it, Dr. Preuss says.
Though Dr. Preuss has an open mind about dietary supplements, he says it's advisable to talk to one's doctor before trying anything. Taking supplements can be especially harmful for people with hypertension and heart disease, he says.
Some foods have been touted as boosting metabolism, but there is little proof of this, says Ms. Snyder of Georgetown University Hospital.
"From a nutritional standpoint, there is no food that revs up your metabolism," she says, adding that eating regularly and not skipping meals can help. "It's not good to skip breakfast because the body will then slow down its metabolism and conserve what it has," she says.
Along the same lines, it previously was thought that yo-yo dieting (also known as revolving-door dieting) might permanently slow down one's metabolic rate. Recent research, however, has shown it doesn't seem to make much difference, Dr. Hirsch says.
"It doesn't seem to mess up your metabolism. … It doesn't seem that important," he says.
Some lucky people appear to have a more efficient basal metabolic rate than others. They may be able to eat 3,000 calories a day without gaining any weight and without doing any additional aerobic or strength exercise.
Those people have an "inefficient metabolic system," Ms. Snyder says. If they were to live on a desert island, they would starve faster than the rest of us. In this society of limitless access to food, however, they may do better than most of us, who feel as if we put on weight merely by looking at a slice of cheesecake.
"It's like the gas mileage on a car. Some cars get 50 miles to the gallon, others get 15 miles to the gallon," Ms. Snyder says. "These people just use more energy [for the same amount of activity]."
The reason some people have a faster metabolic rate than the average person is not completely clear. Some reasons can be genetic, some are based on lifestyle and even on habits such as tapping your fingers or feet all day long.
"Some studies have shown that people who are more fidgety burn more calories," Dr. Clement says. "Their 'idle' is higher."

Adults might like to blame their genetics for letting them get fatter and fatter, but that's neither accurate nor productive, Dr. Clement says.
"The gene pool hasn't changed that much in the last century, but we are getting older, and we have more gadgets and gizmos that allow us to have a more sedentary lifestyle," he says. "Those are some of the real reasons."
Then comes the advice that is so common-sensical and so not-what-we-want-to-hear: A healthy diet and reasonable exercise is the only safe way to lose weight, Dr. Clement says.
The main thing that will increase metabolism is building muscle, which often is a result of aerobic activity such as walking, bicycling, swimming or running, Dr. Hirsch says. It also has been shown that weight lifting, if done safely, can be very beneficial for the 65-and-older crowd.
"As we grow older, physical activity becomes a very important thing to do," he says. "The message is: If you want to do something to boost your metabolism, exercise."

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