> Fitness > Body Mass Index (BMI)

Stepping on the scale is "over weighted." To determine healthy body composition, consider your percentage of body fat in proportion to muscle mass.

Understandably, many of us measure our ideal weight with a scale. Insurance companies and health professionals have used height versus weight scales (body mass indicators, or BMIs) for years to determine overall health. However, these are not always suitably informative because they fail to determine whether a person is muscled or fat.

Scales cannot differentiate between muscle and fat. You will obtain an accurate measurement of your weight, but you do not know how much is lean mass and how much is fat. Lean mass is simply your muscles, bones, connective tissue and organs. The remainder falls into the fat category. You do require a percentage of fat to function, but that consists of only about three per cent of your total body weight.

Studies indicate that, in terms of overall weight, most college-level football players are considered overweight and therefore more susceptible to health risks. In reality, this is far from the truth. The athletes are generally in excellent physical health but have a larger percentage of lean muscle mass.

Proportions Count

When determining your overall health, it’s important to consider your percentage of body fat in proportion to muscle mass. Someone weighing 200 pounds with a body fat percentage of 25 is carrying around 50 pounds of extra fat. That same person weighing 200 pounds with 10 per cent body fat would be carrying around only 20 pounds of fat. This is significant in terms of health, not to mention how exhausting it is to carry around 30 extra pounds of fat. In addition, the person with 50 pounds of fat has only 150 pounds of lean mass to carry that weight, whereas the person with 20 pounds of fat has 180 pounds of lean mass to sustain it. That factor alone will have a dramatic impact on energy level, joint stress and mobility.

Thinner does not always mean healthier, either. Extremely thin people often have a lower-than-desired lean mass percentage. When we do not ingest enough calories, not only do we lose a percentage of our fat, we also diminish the percentage of lean mass. Starvation studies have indicated that parallel losses of lean mass and fatty tissue left subjects with the same percentage of body fat after weeks of starvation. In addition, our metabolic rates diminish as we reduce our percentage of lean mass. Our bodies require far more energy to move lean mass than to move fat. Remember, fatty tissue is an energy source and does not require energy to move. If we have a larger percentage of muscle mass, not only is it easier to move, but we also require more energy to do it. This is why exercise is so important in maintaining a healthy body type. Exercise and movement promotes the utilization of calories as well as the growth of lean muscle mass.

Measuring Up

Fat takes up more than four times as much space as lean muscle mass. So if you want to reduce your size, then reduce your percentage of body fat. An obvious indicator is your waistline. If your pants are becoming baggy but your weight is not changing too much, you know you are heading in the right direction.

Another way to determine body fat is by taking measurements. This is easy to do, cost effective and can be easily monitored. Use a tape measure and record your neck size, chest (just across the nipple line), upper arms around the biceps/triceps region, waist (just below the rib cage, slightly above the navel), thighs and calves. Where applicable, measure both sides of your body and, if possible, measure at the same time of the day. Do this regularly once a week to track your results.

David Lige has a degree in human kinetics from the University of British Columbia. He has worked as a kinesiologist for years and is currently a fitness consultant and personal motivational coach. E-mail: davelige@smartt.com.

Source: alive #248, June 2003