Shattering a few myths about metabolism
By Sally Squires
Washington Post
Rev your metabolism!
That's the calorie-burning promise made by many exercise programs, diet books and dietary supplements. Can they deliver?
"I don't even like the term 'revving metabolism,' " says David Nieman, director of the Human Performance Laboratory at Appalachian State University in Boone, N.C. "There are so many myths involved with this thing."
Sure, big-time bodybuilders — including, at his peak, Arnold Schwarzenegger — can boost metabolism a little, thanks to the extra calories burned by their bulky muscles. But for the typical person, research suggests it's just not possible to alter metabolism significantly.
The best way to keep weight in check is familiar to Everyday Challenge members: Watch your caloric intake.
"It's balancing what you eat with what you do," Nieman says. "If I had to boil down everything I have done in my research to one phrase, it would be this: People who are ultimately successful at weight loss have caloric awareness. They become aware of what they eat and what they burn and are willing to look at the numbers as a daily issue."
Here are some common myths about metabolism — and the sobering reality:
Five to six small meals daily are better than three standard-size meals. Or perhaps, better at fattening you. While it's true eating raises metabolism as the body burns food consumed, the jump in calories burned "is so slight as to just not be meaningful," Nieman says. Also, grazing offers the temptation to eat more, unless those mini-meals are carefully planned and measured. What counts are total calories consumed — not the number of meals. "Having three set times to eat where you make sure of the quality and quantity of the food is far healthier," Nieman says.
Smarter choice: Focus on the quality and quantity of food first and then worry about the frequency.
Exercise keeps metabolism revved for hours. Would that it were so. Physical activity can burn calories while you work out, but the aftereffects are minimal. Studies show that after a typical 20- to 30-minute workout, the body burns about 10 to 12 more calories — about the amount in a bite of an apple. "Metabolism will be back down to normal in about 30 to 60 minutes," Nieman says. Even elite athletes don't have much of an edge here. The number of calories they burn after an intense 90-minute workout, Nieman says: 125.
Smarter choice: When calculating your own daily energy balance, concentrate on calories burned while exercising. Thirty minutes of moderately brisk walking burns about 125 to 150 calories.
More muscle means higher metabolism. OK, it's not a complete myth; muscle does burn more calories than fat. How much more? A measly 7 to 10 calories per pound of muscle per day. "The average enthusiast who goes into the gym only puts on about three to five pounds of fat-free muscle mass over about 12 to 15 weeks," Nieman says. "That adds up to about 28 to 40 calories per day, or about a third of an apple."
Smarter choice: Combine weight training with aerobic activities and lifestyle exercises — like taking the stairs instead of the elevator.
Overweight people have lower metabolism than lean people. Not exactly. Take a 200-pound person whose ideal body weight is 140. "One-fourth of that extra weight is muscle," Nieman says." About 45 pounds would be pure fat. So the average obese individual actually has a slightly higher metabolism than a lower-weight individual." As a healthy weight is achieved, muscle mass is lost along with fat. "The overweight person can't eat like he or she used to," Nieman says, "because their metabolism has gone down in direct proportion to the amount of weight they have lost."
Smarter choice: Continued vigilance in monitoring food and getting enough daily physical activity to achieve and maintain a healthy weight.
