When a health professional assesses a patient's weight and health they commonly use the BMI (Body Mass Index) and waist circumference as indications of health. They use waist circumference specifically because if fat gathers at the patient's waist rather than the hips, they have a greater risk of developing heart disease.
Waist size and health risks
For the average man, the risk is greater if they have a waist bigger than 40". Therefore, one should aim for a waist circumference of less than 40". However, calculating your BMI is believed to be a more efficient way of assessing a persons health as fat can gather in other places other than the waist. The average adult man should aim for a BMI between 18.5 and 24.9.
A 5ft 13yr old boy however who would usually have less developed muscle and would be expected to weigh less should aim for a BMI between 15 and 21.
The table below shows the Mean waist circumference (cm) measured against the age of the sample patient. It indicates that the average boy at 5ft or approximately 153cm should have a waist circumference of 28 inches.
The table below shows the average BMI of teenagers. It indicates that the normal BMI for a 13 year old boy is between 15 and 21.
