Physical health can be measured through the appropriateness of a person's weight to his height; where the body weight refers to the measure of one's heaviness, and the height is the measure of his tallness.

For instance, a woman measuring 5 ft high (1.52 m), with a medium body frame should weigh between 103 lbs to 115 lbs (46.72 kg ? 52.16 kg) to be considered healthy.

Another example: a man standing 5 ft 8 in (1.72 m) tall, with a large body frame is healthy if he is weighing between 144 lbs ? 163 lbs (65.32 kg ? 73.94 kg). Otherwise, if their weight is lower than the desired body weight for their height, they are considered underweight, and if, in turn, their weight is higher than the desired body weight for their height, they are said to be overweight.

Body Mass Index (BMI)

Body Mass Index is an accurate indicator of surplus body fat than kilos or pounds. It is a mathematical ratio of height to weight that can be linked with body composition (or body fat percentage) and with indices of health risk.

Calculating BMI is as follows:

BMI = Weight (in kg)/Height (in m)?
or
BMI = Weight (in lbs) x 700/Height (in inches)?

For example, the calculation for someone weighing 80 kg (176 lbs) and 1.60 m (63 in) tall is:

BMI = 80/160? = 31.2
or
BMI = 176 x 700/63?= 31.1

People with a BMI of 25.1 to 29.9 are considered overweight, and people with a BMI of 30 or above are considered obese. Thus, from the example above, a person weighing 80 kg and is 1.60 m tall is obese. A high BMI assumes a higher percentage of body fat, which places a person at greater risk for developing chronic diseases and other serious illnesses.

BMI and Weight Category:

Under 19: Underweight
20-25: Normal (Healthy)
26-30: Overweight
30 above: Obese

However, for some people, the BMI is not a reliable indication of health. A highly muscled individual who is very fit and healthy may have a somewhat heavy body weight because muscles pack on a lot of pounds. This person may have a high BMI that improperly puts him or her in the overweight or obese categories.

Likewise, thin individuals who have a low body weight with very little muscle and a higher percentage of fat may have a normal BMI, which would be an incorrect indication of healthiness.