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All about obesity

Obesity is a disease that develops when there's an excess amount of body fat that affects your health and can increase your risk of long-term medical conditions such as:

Obesity is a progressive disease, which means that it requires long-term management. With support and guidance, obesity is manageable. 


How to screen for obesity

To find out if you're living with obesity and to get a formal obesity diagnosis, it's important to talk to your healthcare professional. One simple way to screen for obesity is to calculate your body mass index (BMI).

BMI classifies underweight, overweight and obesity in adults based on their height and weight. Here you can see the BMI classifications

BMI Classification  Underweight: Below 18.5 kg/m²
   Normal: 18.5 to 24.9 kg/m²
   Overweight: 25.0 to 29.9 kg/m²
   Obesity Class I: 30.0 to 34.9 kg/m²
   Obesity Class II: 35.0 to 39.9 kg/m²
   Obesity Class III: 40.0 to 49.9 kg/m²
   Obesity Class IV:  50.0 to 59.9 kg/m²
   Obesity Class V: Above 60 kg/m²

Cut-offs are different for people of South-, Southeast- or East Asian descent.

Remember, BMI should only be used as an obesity screening tool. Together with other clinical tests, BMI can be used to identify people who may benefit from obesity management. 

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What are the symptoms of obesity?

The symptoms of obesity go beyond excess body fat. If you're living with obesity, you may experience a variety of common symptoms. These can include:

  • Difficulty doing physical activities like climbing stairs
  • Breathlessness
  • Increased sweating
  • Snoring
  • Feeling tired regularly
  • Joint pain
  • Back pain
  • Low confidence and self-esteem
  • Feeling isolated
  • Depression, anxiety and mood disorders

If these symptoms sound familiar, it may be a good idea to talk to your healthcare professional. Understanding obesity and available treatments can help manage your weight.

How does losing weight improve your health?

See the benefits of losing even 5% of your body weight

Check your BMI with a BMI calculator

Body mass index (BMI) is an important measurement when it comes to understanding your weight. While it should not be used to diagnose obesity, it can be used as a screening tool to classify your weight.

Find your BMI and health risks

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  1. Wharton S, Lau D, Vallis M, et al. Obesity in adults: a clinical practice guideline. CMAJ. 2020; 192(31) 875-891.

  2. Rueda-Clausen CF, Poddar M, Lear SA, et al. Canadian Adult Obesity Clinical Practice Guidelines: Assessment of People Living with Obesity. Accessed November 22, 2022. https://obesitycanada.ca/guidelines/assessment/

  3. Obesity. National Health Service.  Accessed November 22, 2022. https://nhs.co.uk/conditions/obesity