Another valuable calculation we will use is the Body Mass Index (BMI). The BMI is calculated from a person's weight and height. It is a fairly reliable indicator of body fatness for most people, but it does not measure body fat directly. The gold standards for calculating body fat are methods such as underwater weighting and dual energy x-ray absorptiometry. However, research as shown BMI to be an acceptable and accurate way of measuring body fat.
BMI is a screening too only, not a diagnostic tool. For example, a person may have a high BMI. However, to determine if excess weight is a health risk, a healthcare provider would need to perform further assessments like skin fold thickness measurements, evaluations of diet, physical activity, family history, and other appropriate health screenings.
To caclulate BMI, the following method is used:
Formula: weight (pounds) / [height (in)]2 x 703
(divide weight in pounds (lbs) by height in inches (in) squared and multiplying by a conversion factor of 703.)
For example: Weight = 150 lbs, Height = 5'5" (65")
Calculation: [150 ÷ (65)2] x 703
Calculation: [150 ÷ (65)2] x 703
[150 ÷ 4225] x 703
= 24.96
So, what does this calculation mean?
BMI | Weight Status |
Below 18.5 | Underweight |
18.5 – 24.9 | Normal |
25.0 – 29.9 | Overweight |
30.0 and Above | Obese |
There is a strong correlation between the BMI number and body fatness; however the correlation varies by sex, race, and age. Also, highly trained athletes have a higher BMI because they have a lot more muscle than the average person.
It is also important to remember that BMI is only one factor related to risk for disease. Two other important predictors are:
· The individual's waist circumference (because abdominal fat is a predictor of risk for obesity-related diseases).
· Risk factors the individual has for diseases and conditions associated with obesity (for example, high blood pressure or physical inactivity).
Being overweight has numerous detrimental affects on your health, inlcuding hypertension, abnormal lipid counts, Type 2 diabetes, stroke, and cancer.
As you can see, it is important for you to keep track of your BMI. So, you need to calculate this number now and write it down for reference.
