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DIAGNOSE: BMI and waist circumference

BMI and waist circumference are important measures for evaluating obesity-related health risks.There are several things that you as a healthcare provider can do in order to make this experience as comfortable for your patient as possible.

When weighing your patient:

  • Ensure weighing scales are in an area which offer privacy
  • Ensure weighing scales measure greater than 200 kg
  • Refrain from announcing your patient’s weight in a non-private area

Assess BMI (Body Mass Index)

Diagnosing obesity begins with assessing your patient’s BMI – this is a simple measurement of your patient’s weight (kg) divided by the square of their height in metres.2

The World Health Organization propose a BMI-centric classification system to guide population level and clinical decision-making strategies.2





Obesity class I

≥30 and <35

Obesity class II

≥35 and <40

Obesity class III


Measure waist circumference

Waist circumference is an important measure for evaluating health risks. Below is a guide on how you can make this a more comfortable experience for your patient:1

  1. Ask the person to stand facing you
  2. Hand them one end of the measuring tape and ask them to hold it at their belly button
  3. Request they make one turn so that the tape wraps around their waist
  4. Grasp both ends of the tape and adjust it to ensure the tape is at the level of the upper hip bones and record their waist circumference

Waist circumference cut-offs to identify increased relative risk for the development of obesity-related complications3


> 102cm


> 88cm


1.     NHLBI. The Practical Guide Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. Available at: https://www.ncbi.nlm.nih.gov/books/NBK2003/. Last accessed: October 2020.

2.     WHO. Obesity: Preventing and managing the global epidemic. Available at: http://www.who.int/iris/handle/10665/42330 Last accessed: October 2020.

3.     Durrer Schutz D, Busetto L, Dicker D, et al. European Practical and Patient-Centred Guidelines for Adult Obesity Management in Primary Care. Obes Facts. 2019; 12:40–66.

HQ20OB00138, Approval date: December 2020

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