By Angela Stringfellow on June 2, 2011 in
Bathroom scales are a popular weight-loss tool, but body weight alone doesn't paint a complete picture. Two people, each weighing 300 pounds, can look drastically different, and one can be far healthier than the other. That's because muscle weighs more than fat, which is also why individuals who undertake a diet and exercise program find themselves frustrated that they're not dropping pounds. Exercise builds muscle mass, which compensates for any fat lost.
Enter the body-fat scale
More complicated than the "step and, voila, your weight in pounds appear" bathroom scales, body-fat scales use electrodes that send a small electrical current through your body to estimate your body composition. This is usually measured in a percentage (e.g., 30 percent body fat means 30 percent of body mass is comprised of fat). Body-fat scales take a lot of heat for being inaccurate; some experts say they can be off as much as 9 or 10 percent, while others say it's closer to 4 or 5 percent.
A 2007 review in The New York Times tests this theory, comparing body-fat percentage estimates from four body-fat scales to figures obtained through underwater weighing. This technique measures the amount of water displaced when the body is submerged to determine body composition and is considered one of the most accurate methods for measuring body fat. The Health o Meter BFM884 was the most accurate of the four models tested, giving a reading just 0.1 percent off from the hospital test. All four were within 4.1 percent of the accurate reading. Still, consumers frequently point out that when compared with more accurate measurement methods they've had taken elsewhere, body-fat scales are seldom on the money in terms of body fat.
Richard Pierson Jr., MD, professor of clinical medicine at Columbia University tells Muscle and Fitness Hers magazine that knowing the correct percentage isn't that important. As long as the scale gives consistent readings, body-fat scales are a practical way to monitor changes over time. In fact, Pierson says this method is more accurate at tracking short-term changes than measurements taken with skinfold calipers, because body-fat scales can detect changes in visceral fat (that which tends to form around organs) before a measurable loss in skin folds would be apparent.
If you're using a body-fat scale to track your progress, experts say they should be used under the same conditions each time. Walking expert for About.com, Wendy Bumgardner, says that dehydration can affect readings, so it's best not to use these scales first thing in the morning, immediately following a workout or after consuming alcohol. Three hours after a meal is best, after you've emptied your bladder. (Note that ConsumerSearch is owned by About.com, but the two don't share an editorial affiliation.)
Cut the fat, but don't stop there
Here's the bad news: Even body-fat percentages aren't a stand-alone indicator of good health. According to Cynthia Sass, registered dietician and contributing editor for Shape magazine, age, height, weight, body fat, activity level, diet, waist circumference (less than 35 inches for women, 40 inches or less for men), sleep and stress levels all play a vital role in overall health.
The best way to influence these factors is to adopt a good diet and exercise plan. What does that entail? James O. Hill, PhD, Director of the Center for Human Nutrition at the University of Colorado, told WedMD.com that a long-term commitment to daily physical activity and a low-fat, high fiber diet should do the trick. It's possible to lose weight without exercise, by cutting back drastically on calories, but exercise is key to keeping the weight off. Hill finds that those who are most successful at keeping weight off over time eat breakfast and have about 60 to 90 minutes of physical activity each day.
Not the "get-skinny-quick" solution you were hoping for? Using diet pills may be tempting, but Hill says they're most effective when combined with a healthy diet and exercise. And if undertaking this mission on your own seems overwhelming, enlist a buddy who wants to get healthy, too, or join a weight-loss program for motivation.