Monday, November 15, 2010

How much should I weigh

The weight which is just right for your body is determined by several factors, such as sex, age, height, muscle-fat ratio, bone density, etc. However, the ideal body weight depends on ethno-historical, cultural and professional factors, as well. So, if you are neither a fashion model nor a sumo-wrestler, you could use one of the following ways to calculate your ideal body weight: Body Mass Index, Waist-hip Ratio and Body Fat Percentage.

Body Mass Index (BMI) is a measure that relates your weight to your height. You can calculate it by dividing your weight in kilograms by the square of your height in meters. For example: if you are a woman who is 1.60 meters tall and weighs 60 kilograms, your BMI is 23.44 (1.60 x 1.60 = 2.56; next: 60 divided by 2.56 =23.44).
If you use imperial units instead of metric ones, you should time (703) your weight in pounds and divide it by the square of your height in inches. For example: if your weight is 150 pounds and your height is 65 inches, your BMI is 24.95 (65 x 65 = 4225; 150 x 703 divided by 4225 =24.95).

Your weight is ideal if your BMI ranges between 18.5 and 25. You are underweight if your BMI is less than 18.5, and overweight with a BMI between 25 and 30. People with a BMI over 30 are classified as obese. However, the biggest problem with the BMI is the fact that BMI ignores some factors of great importance, such as bone density, muscle-fat ratio, waist-hip ratio, etc. For instance, people suffering from severe osteoporosis have very low levels of bone density. So, they would have a lower BMI than others of the same height who are healthy. The trained athletes have more muscle tissue and less body fat than will have couch potatoes of the same height. For this reason, athletes have a higher BMI.

Waist-hip Ratio (WHR) is the ratio of your waist's circumference to that of your hips. To calculate your WHR, you need to measure the circumference of your waist (just above the belly button) and the circumference of your hips (at their widest part). Then, you have to divide the first result by the second one. For instance: if your waist is 60 centimeters and your hips are 90 centimeters, your WHR is 0.67.
The WHR determines the ideal weight of a person and the risk of cardiovascular health problems, as well:

For females:* WHR less than 0.8 - low risk
* WHR between 0.8 and 0.89 - moderate risk
* WHR over 0.89 - high risk

For males:* WHR less than 0.9 - low risk
* WHR between 0.9 and 0.99 - moderate risk
* WHR over 0.99 - high risk

The problem with the WHR is the lack of measurement on the muscle-fat ratio, but the WHR is a more effective predictor of the ideal body weight than the BMI.
The Body Fat Percentage (BFP) is the ratio of your body fat divided by your total weight. BFP also indicates the person's storage of fat. The most popular ways of calculating the BFP are: dual energy X-ray absorptiometry, near-infrared interactance, and bioelectrical impendance analysis.