What the Scale Misses
At one time or another you have almost certainly stepped onto a scale to check your body weight. But relying on the scale to tell you if you're at a healthy body weight can be frustrating. Understanding what the scale does and does not tell you will help you keep the scale's information in perspective.
The Difference Between Fat and Muscle
A scale measure your total body weight in kilograms. It does not measure how many of those kilograms are muscle, bones, blood, etc and how many are fat. Exercise physiologists call this ratio your body composition, typically referred to as a percent body fat.
Focusing on the number on the scale is problematic because you don't know how many pounds are from fat and how many are from muscle. You may have heard the "muscle weighs more than fat". That's not true. A kilogram of muscle weighs the same as a kilogram of fat, one kilogram. However, fat and muscle differ in an important way – muscle is much denser than fat. Think of it this way. Muscle is like a brick. Fat, on the other hand, is like cotton balls. It take far more cotton balls than a brick to make a kilogram. So a kilogram of fat takes up more space on your body than a kilogram of muscle.
Let's examine how judging yourself solely by scale weight can be misleading. Let's say you are sedentary and decide to start a fitness program that includes moderate to vigorous aerobic exercise for 20-30 minutes three to four days per week, and strength training two to three days per week. If you combine this workout schedule with a sensible, adequate-calorie diet, research suggests you could potentially lose one to two pounds of body fat per week.
Your new fitness lifestyle could help you to lose, say, 5 kilograms of fat in the next three months. In addition, your strength training program could help you to gain about 1.5 kg of lean muscle weight, a very positive change. If you used your scale as your only reference point, you might be tempted to think your new lifestyle wasn't working very well, because you'd see only a 3.5 kilogram loss. But rest assured that you would have made truly positive changes.
Because of fat's low density, you'd probably see the 5 kilogram loss as small circumference measurements around your stomach, hips and thighs. That's why paying attention to the way your clothes fit is generally considered a better way to assess your progress than focusing on the scale.
If you went just by the scale's number, you might be tempted to skip strength training, and that would be a shame. Additional muscle tissue not only helps you become stronger, making daily activities easier to accomplish, it also has an extra long-term advantage: Muscle tissue expends calories all day long, even when you are at rest. Over the course of a year, a few added kilograms of muscle can help you burn thousands of additional calories.
Getting Real About Weight
Keep in mind that your body weight can fluctuate by a kilogram or so over the course of a day. This is especially true if you exercise fairly vigorously. The flucation is due to changes in the amount of water in your body. If you weigh yourself before and after an exercise session, you might find you've loss a kilogram. It's just water loss.
Likewise, if you weigh yourself right after a big meal, the scale might show you've gained weight. Additionally, women often show their weight fluctuations in relation to hormonal changes during their monthly menstrual cycles. Checking the scale no more than once every week or two is usually the best.
How much should you weigh? Health and fitness professionals frequently debate this question, but there's no clear-cut answer. If you have not risk factors, such as high blood pressure, high cholesterol or Type II diabetes, and adopt an active lifestyle that incorporates regular exercise and sensible eating, the weight you achieve over time will likely be your healthy weight. Patience and persistence are the keys.
Accurately measuring changes in percent body fat is an excellent way to track your exercise progress. To find out your percentage body fat, consult with a qualified fitness professional. He or she is likely to use either a skinfold caliper or the circumference measurement technique, both common methods.