The acceptable range of normal adult body mass index is?

Appeared in: KPSC Staff Nurse - 2015

Explanation

The World Health Organization (WHO) defines a normal adult BMI as being between 18.5 and 24.9 kg/m².
This range is associated with the lowest risk of developing various chronic diseases linked to weight.
BMI is a simple and effective screening tool calculated by dividing a person's weight in kilograms by the square of their height in meters (kg/m²).

Option A: This range begins at 15.3, which is classified as underweight (BMI less than 18.5). While it extends into the normal range, it does not represent the full, acceptable normal range.
Option C: This range starts within the upper limit of normal but extends to 28.5, which is firmly in the 'overweight' category (BMI 25.0–29.9).
Option D: This entire range falls outside the normal classification. A BMI of 25.0–29.9 is 'overweight', and a BMI of 30.0 or greater is 'obese'.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Normal Body Mass Index (BMI) range for adults as background academic context rather than a clinical decision trigger.
Nurses routinely calculate and monitor BMI as a vital part of health assessments to screen for nutritional imbalances and risk for conditions like heart disease, diabetes, and hypertension.
BMI is a key component of patient education, helping nurses explain the importance of maintaining a healthy weight through diet and exercise.
What if? If a patient is a muscular athlete with a BMI of 28 (overweight), a nurse should use clinical judgment. The high BMI is likely due to increased muscle mass, not excess fat. In such cases, waist circumference or body fat percentage would be a more accurate measure of health risk.

How to Approach the Question

First, identify the key terms in the question: 'acceptable range', 'normal', 'adult', and 'body mass index (BMI)'.
This is a factual recall question. Access your knowledge of standard health metrics.
Recall the WHO classification for BMI. The critical cut-off points are 18.5 (separating underweight from normal) and 25.0 (separating normal from overweight).
Scan the options to find the range that matches the 'normal' classification, which is 18.5 to 24.9.
Systematically eliminate the other options by comparing them to the standard BMI categories (underweight, overweight, obese).

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 1 — Subpart C (pp 404-604 of 604) p. 69-71

Practise the full KPSC Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.