According to the WHO adult classification, a BMI i – Class 12 Physical Education

Concept understanding — BMI Classification

BMI Classification: A Concept-First Explanation

Think about how we describe a person's build in everyday language. Someone might be "lean," "stocky," "heavyset," or "slim." These words are useful but imprecise — what one person calls "stocky," another might call "average." BMI Classification is a system that replaces these vague descriptions with a standardised, objective scale.

The Core Idea

BMI stands for Body Mass Index. It is a single number that relates a person's weight to their height. The fundamental intuition is simple: a taller person naturally carries more weight than a shorter person, so we cannot judge body size by weight alone. BMI adjusts for height, giving a number that can be compared across people of different statures.

The classification system then takes that number and places it into one of several categories. These categories are not arbitrary — they are based on large-scale population studies that link each range to different levels of health risk.

The Classification Categories

The standard classification divides BMI values into these ranges:

Underweight — a BMI below a certain threshold
Normal weight — a BMI within a healthy range
Overweight — a BMI above the normal range but below obesity
Obese — a BMI above a higher threshold, further subdivided into classes

Important

BMI Classification is a screening tool, not a diagnostic one. It tells you whether a person's weight falls into a range associated with higher or lower health risks, but it does not measure body fat directly, nor does it account for muscle mass, bone density, or fat distribution.

Why It Matters

The value of BMI Classification lies in its simplicity and its statistical power. For populations, it is an excellent predictor of trends — rising obesity rates, for instance, show up clearly in BMI data. For individuals, it provides a quick, non-invasive starting point for a conversation about health.

A person classified as "normal weight" is, on average, at lower risk for conditions like heart disease, diabetes, and joint problems. Someone classified as "obese" faces elevated risks for these same conditions. But the key word is "average" — a muscular athlete may have a high BMI with excellent health, while a person with a "normal" BMI may have poor metabolic health. …

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A BMI of 18.5–24.9 kg/m² is the WHO’s “Normal (healthy) weight” range for adults.

This is a straightforward MCQ that tests your recall of the World Health Organization’s international adult BMI classification. The question gives you the range and asks which label it corresponds to.

The BMI (Body Mass Index) is a simple screening tool that relates a person’s weight to their height. It is calculated as:

BMI = (weight (kg))/([height (m)]²)

The WHO divides the resulting number into four main categories for adults. The range 18.5–24.9 kg/m² is the normal or healthy weight zone. People in this band generally have the lowest statistical risk of weight-related health problems.

Here is the full WHO international classification for adults:

BMI (kg/m²)	Classification
Below 18.5	Underweight
18.5 – 24.9	Normal (healthy) weight
25.0 – 29.9	Overweight
30.0 and above	Obese

Now look at the options:

(a) Underweight — This is for a BMI below 18.5, not the given range. …

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Q.According to the WHO adult classification, a BMI in the range 18.5 – 24.9 kg/m² is classified as:

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