How can we calculate the body mass index and how should we use it is it always reliable?

You can calculate the BMI by the equation weight / height by meter square

<18.5 underweight 

18.5 -22.9. Normal

23 -24.9 overweight 

25 -29.9 moderately obese 

>30 several obese 

You can calculate the BMI by the equation weight / height by meter square

BMI=BODY WIGHT OVER SQUARE HIGHT OF THE PERSON

ITSELF

BMI is usually done for measuring weight in relation to height. it is calculated by Adolphe Qutelete formula as: weight in Kg/ Height in meter square.

and it can be graded according to WHO as...

BMI < 18.5 =underweight

18.5-25 = normal (healthy weight)

25-30 = overweight

30-35 = grade I Obese (moderately obese)

35-40 = grade II Obese (severely obese)

>40 = grade III obese ( very severely obese)

Simply BMI is your current weight in (Kg) divided on your squared hieght in (cm).

if the result less than 18.5 you considedred underweight

18.5-24.8 normal

25-29.9 overweight

30-34.9 obese grade 1

35-39.9 obese grade 2

more than 40  morbidly obese 

it`s not reliable for athletes, or  if edema present

An excerpt from our Nutrition Education Curriculum:

BMI is used as a screening tool to identify possible weight problems for adults; BMI is not a diagnostic tool.

For example, a person may have a high BMI; To determine if excess weight is a health risk, a healthcare provider would need to perform further assessments; These assessments might include skinfold thickness measurements, evaluations of diet, physical activity, family history, and other appropriate health screenings