Question

Explain the procedure for calculating the Body Mass Index.

Answer 1

Body Mass Index is a screening tool that indicates whether a person is underweight, has a healthy weight, is overweight, or is obese. A high BMI may indicate excess body fatness, but it is not diagnostic of an individual's body fatness or health.

Formula \[\text{BMI} = \frac{\text{Weight (in kg)}}{(\text{Height (in m)})^{2}}\]

Equipment required: Flat, clean surface; electronic/digital weighing machine; stadiometer or measuring tape pasted on a wall.

Procedure for measuring height accurately:

1. Ask the participant to remove shoes, bulky clothing, hair ornaments, and to unbraid hair that may interfere with measurement.
2. The flooring should not be carpeted; measure against a flat wall without moulding.
3. The participant should stand with feet flat and together, back against the wall, legs straight, arms at the sides, and shoulders level.
4. The participant should look straight ahead so that the line of sight is parallel to the floor.
5. The head, shoulders, buttocks, and heels should touch the wall as far as the body shape allows.
6. Use a flat headpiece to form a right angle with the wall; lower it until it firmly touches the crown of the head.
7. The measurer's eyes should be level with the headpiece.
8. Lightly mark where the bottom of the headpiece meets the wall. Measure from the floor to the mark using a metal tape.
9. Record the height accurately to the nearest 0.1 cm.

Procedure for measuring weight accurately:

1. Use a digital scale placed on firm flooring such as tile or wood, not carpet.
2. The participant should remove shoes and heavy clothing.
3. The participant stands still, faces forward, keeps arms at the sides, and places both feet in the centre of the scale.
4. Record the weight to the nearest decimal fraction, for example, 25.1 kg.

Scoring: Height is recorded in cm and mm; weight is recorded in kg and g. Substitute the weight in kg and height in metres into the BMI formula. The result indicates weight category and possible health risk. A BMI outside the healthy range is a warning sign, not a final diagnosis.