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Classification Under-weight

Your result:

BMI Classification Table
BMI Classification
Under 18.5 Underweight
18.5 - 24.9 Normal Weight
25-29.9 Overweight
30-34.9 Obesity Class I
35-39.9 Obesity Class II
Over 40 Obesity Class III

*This BMI calculator is for adults 20 years or older. Talk to your doctor about your BMI if you're under the age of 20.

What does this mean for you?

A BMI of 18.5 or less falls below the normal range and means you’re underweight. You may not have the same health risks as people living with obesity, but being underweight could be putting you in other risk categories. Contact your healthcare provider for an evaluation or help getting your nutrition on track.

Frequently asked Questions

Why is BMI important to know?

While underweight individuals may not face the same health risks as those living with obesity, it's important to acknowledge that there are still significant health concerns associated with being underweight. BMI is a good way to check your risks of health conditions related to being underweight. In general, the lower the BMI the greater the likelihood of developing health complications such as:

  • Osteoporosis
  •  Infertility
  • Impaired immunocompetence

Ask your doctor for more information about any of these conditions and how they relate to your BMI.

What are the limits of BMI?

BMI is a simple and objective measurement, but it can be misleading in certain cases and for some groups of people. Research has shown that BMI is less accurate in predicting the risk of disease in people who are older, athletes, those who are tall or short, and those with more muscular body types. For example, elite athletes or bodybuilders have more muscle and weigh more, which makes their BMI higher.

BMI also doesn't take into account:

  • Hereditary risk factors associated with obesity-related diseases, such as metabolic syndrome
  • Environmental and lifestyle factors that can contribute to your risk of developing chronic disease
  • How body fat is distributed in individuals

It's important to remember that living with obesity doesn't necessarily mean you're unhealthy, just as being at a ‘normal’ weight doesn't mean you're healthy. Your BMI doesn't define you, but knowing and understanding your BMI can be a powerful tool for taking charge of your own health.

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