Using The Power Of Your Metabolism
Have you convinced yourself that your passion for chocolate or your chips-and-dip habit isn’t the real reason those jeans no longer fit? And that it’s all the fault of your slow-motion metabolism? Well, forget that excuse. New research reveals that we can all get our bodies to burn calories faster. Below, experts address your most burning questions about charging up your metabolism.
What exactly does metabolism mean, anyway?
Your metabolic rate is the speed at which the body burns calories at any given time. Most people know that the pace picks up during exercise. But what many don’t realize is that when it comes to losing weight, the number of calories burned when you’re doing absolutely nothing matters most! Your resting metabolic rate (RMR) — how fast you expend energy for basic functions like breathing and blood circulation — accounts for up to 75 percent of the total number of calories you use up daily.
What determines the speed?
The most important factor: how much “fat free” mass your body contains — including muscles, organs, and bones. “The larger your frame and the more toned your body, the faster your RMR,” says James 0. Hill, Ph.D., professor of medicine at the University of Colorado Health Sciences Center in Denver.
Men naturally have more fat-free mass than women. Age plays a role, too; as the years pass, we lose muscle — a major energy consumer. We also tend to inherit RMRS that are similar to our mother’s or father’s, though who we take after is potluck.
Does my body naturally qravitate toward a certain weight?
Some experts insist that the body has a genetically preprogrammed weight, or “set point,” and that the metabolism does whatever it can to keep you there. A 1995 study conducted at The Rockefeller University in New York City backs this up. “The results suggest that when you drive weight down, the body makes adjustments to try to bring it back to where it used to be,” explains study coauthor Jules Hirsch, M.D. But don’t despair; there are scientists who believe that this dip is temporary, and that the metabolism rebounds and restabilizes once you’ve maintained your new weight for six months or so.
Is it a given that I’m going to get fatter as I get older?
Resting metabolism typically does decline after age 25, when we start to lose a half pound of muscle a year. As a result, with each passing decade we burn approximately 100 fewer calories a day. But you’ll only gain significant weight if you take this lying down. “People who are sedentary metabolically age at a much faster rate than those who stay active,” says Susan Roberts, Ph.D., associate professor of nutrition at Tufts University in Boston. “In addition, studies indicate that starting an exercise program at any age can slow, even reverse, the effects of aging on resting metabolism.”
Does menopause play a role?
Perhaps. In a long-term study at the University of Maryland in Baltimore, researchers followed 35 women for six years and found that those who went through menopause gained three to five pounds of body fat, lost about six pounds of muscle, and experienced a drop in RMR of 103 calories per day. The women who remained premenopausal experienced no change in body composition or metabolism. “It’s possible that estrogen plays a role in the maintenance of muscle mass,” says study director Eric Poehlman, Ph.D. Researchers are exploring whether estrogen replacement therapy may help.
Can a high-protein diet help burn food faster?
Yes, but only to a very small extent. The problem is, the most common sources of protein-meat, cheese, and nuts — are chock-full of fat. “So you increase calorie intake, which in turn cancels out any slight metabolic advantage you may have gained,” points out J.P. Flatt, Ph.D., a professor of biochemistry at the University of Massachusetts Medical School in Worcester. Moreover, some doctors say that a high-protein diet can leach calcium out of the bones, raising your risk of osteoporosis. Aim for a diet that’s 55 to 60 percent carbs, 15 to 20 percent protein, and 20 to 25 percent fat.
Could a low-calorie diet do more harm than good?
Definitely. “The body perceives significant calorie deprivation as a threat to its existence and slows down in a noble effort to conserve calories,” says Stephen Farrell, Ph.D., associate director of the Cooper Institute for Aerobics Research in Dallas. Most experts believe that the danger begins when you dip below 1000 calories a day.
If you want to take off pounds, reduce food intake to no fewer than 1200 calories a day (and exercise more). But don’t worry if you haven’t followed such prudent advice in the past: Contrary to previous reports, “yoyo dieting does not seem to put a permanent damper on the metabolism,” says Hill. Once you resume a more realistic eating regimen, your metabolism gets back up to speed.
Is it possible to metabolism by eating frequent small meals instead of three square-meals per day?
“If there is any advantage to spreading out calories, it’s small and not worth changing your lifestyle for,” says David B. Allison, Ph.D., a research scientist at the Obesity Research Center at Columbia University College of Physicians & Surgeons in New York City. Some experts do believe, however, that metabolism is at its peak form during the first 12 hours after waking.
Are there any drugs I can take?
Yes, but don’t. Many of the so-called fat-burning diet pills you see at health food stores are made with ephedrine (or ma-huang, the herbal form), a compound that has been shown to stimulate RMR. But it causes dangerous side effects, including an irregular heartbeat, which can lead to cardiac arrest. As for other popular “metabolic boosters” like chromium picolonate, inositol, and capsaicin, don’t waste your money. “They may not hurt you,” says Nancy Rodriguez, assistant professor of nutritional sciences at the University of Connecticut at Storrs, “but they’ve never been shown to have a significant effect on metabolic rate or body weight.”
Some common everyday substances may slightly boost metabolism. Two cups of caffeinated coffee bum up an extra 50 calories a day. Nicotine also elevates metabolism, one reason why smokers weigh, on average, eight pounds less than nonsmokers. But the risks of lighting up regularly overwhelmingly outweigh any possible benefit to your waistline.
Does your rate stay elevated after you work out?
It depends on the workout. Doctors now know hat aerobic exercise — like walking, cycling, or swimming — doesn’t actually offer much in the way of a postworkout bum. A study conducted at Columbia University in New York City revealed that after a moderate workout (a brisk 30-minute walk), RMR remains revved up for about a half hour — good for only an extra 15 or 20 calories. “The main calorie-burning benefits take place while you’re exercising — about 200 to 300 calories per hour,” points out researcher Barbara Brehm.
Strength-building exercises deliver the biggest postworkout results, according to two studies published in the Journal of Applied Physiology. After 45 minutes of weight lifting or calisthenics, for example, the metabolism should stay elevated for four to six hours; you burn an extra 60 to 80 calories.
One surprising reason why some people are able to stay skinny so effortlessly: They’re natural-born fidgeters. According to a study conducted by the National Institutes of Health in Phoenix, chronic finger-drummers, foot-tappers, and pacers burn several hundred more calories per day than relaxed types.
How much exercise do I have to do to get any benefits?
Experts recommend that you do a half hour of moderate aerobic activity at least three times a week for instant calorie burning, plus toning exercises to keep your metabolism primed. Two 20-minute sessions of weight lifting, push-ups, crunches, or leg lifts per week should do the trick, says Wayne Westcott, fitness research director at Boston’s South Shore YMCA. Use the machines at a local health club, YMCA, or community center, or buy a set of three- to five-pound dumbbells and a toning video geared for beginners.
Stick to your routine for two to three months and you’ll build enough muscle to bum up to 100 extra calories daily — even on days when you’ve barely lifted a finger.