Question

Define body mass index

Answer 1

Hey There! ☺

BMI is the abbreviation for Body Mass Index which is also known as Quetelet Index.

It is the ratio of our weight (kg) to the square of our height (m).

As the definition states, it is very easy to be calculated.

Formula of BMI is :

 $\frac{Weight (kg)}{Height ^{2}(m) }$

That is, we can calculate BMI by dividing our weight in kilograms with the square of our height in metres.

Example :

Consider an adult of height 1.6 m & weight 54 kg.

Then, BMI = 54 / (1.6 x 1.6) = 21 [approx.]

Purpose :

BMI is calculated to know about the nourishment of an adult.

Each BMI value indicate the nourishment status such as under weight, normal weight, over weight & obese.

♦ If BMI < 18.5, the person will be considered undernourished.

♦ If BMI > 25, the person will be considered overweight.

♦ If BMI > 40, the person will be considered obese.

♦ If BMI is between 18.5 & 24.9, the person has a healthy weight.

An infograph of Body Mass Index is attached for more info.

To get accurately your nourishment status with reference to your BMI value, BMI Charts are commonly available.

Remember : BMI is applicable for adults only & can't be used to calculate nourishment status of growing children.

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Hope my answer helped! ☺ Stay Healthy! ♥

Answer 2

Hey There! ☺️

What is BMI?
BMI (Body Mass Index) is a measure of body's fat based on height and weight that applies to adults more than 20 years of age. It is an excellent measure to assess our risk of health complications as it can guide us in our quest to better health. 
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How BMI is calculated? 
Calculating BMI is one of the best methods for population assessment of overweight and obesity. BMI is a weight to height ratio calculated as weight in kilograms divided by height in metres squared. 

$To \: calculate \: BMI \: \\ BMI = \frac{weight(kg)}{height(m) {}^{2} }$
That is, we can calculate BMI by dividing our weight in kilograms with the square of our height in metres.

For Example:

Q. Calculate the BMI of a patient who weights 78kg and is 182 cm tall. 

Sol. The index works with metres, not centimeters, so first we have to convert cm to m by dividing from 100
182cm/100 = 1.82 m

The formula tells us how to do calculation:

$BMI = \frac{78}{1.82 \times 1.82} = \frac{78}{3.31} = 23.6$
This patient is comfortably inside the normal healthy weight range as BMI is less than 25

If BMI < 18.5, then person is undernourished.
If BMI > 25, then person is overweight. 
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How does BMI indicate about adult nourishment? 
Body Mass Index is calculated to be aware of through observation about the food necessary for growth, health, and good condition of a fully developed person. 

The value of each BMI shows the action of nourishing an individual such as insufficient weight, common or expected condition of weight,excessive grossly fated weight. 

♦ If Body Mass Index is less than 18.5 (BMI<18.5), then the individual will be considered as an undernourished which means means that he/she was having insufficient food or other substances for good health and condition.

♦ If Body Mass Index is greater than 25 (BMI > 25), then the individual will be considered as an overweight who has having above a weight considered normal or desirable.

♦If Body Mass Index is greater than 40 (BMI > 40),then the individual will be considered as an obese who has having grossly fat or overweight.

♦If Body Mass Index is between 18.5 and 25.9, then the individual will be considered as a healthy living being who is enough fit and healthy. 

A visual representation of this information (BMI) 
is attached in the attachment of this information to give more information as a good infographic is a worth of thousand words

To get specifically your status of nourishment with mention to your Body Mass Index value, are frequently accessible. 

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Hope my answer helped! ☺ 
Eat healthy, exercise regularly, and stay healthy to improve your BMI score! ♥