If you’ve already looked into getting bariatric surgery, then you’ve probably heard the question: what is body mass index?

Put simply, it’s your body mass divided by the square of your height.

This is currently our best way to determine if someone is underweight, at normal weight, overweight or obese. It’s been the World Health Organization’s standard for determining obesity since the 1980s. 

In Oklahoma, our state’s obesity level is unfortunately one of the highest in the country – we currently rank 8th out of 51 states.

You can calculate your Body Mass Index here. Once you’re finished, we’ll let you know what it means.

Standards for assessing BMI

The numbers and designations go as follows:

  • > 18.5 kg/m2: underweight
  • Between 18.5 – 25 kg/m2: normal
  • Between 25 – 30 kg/m2: overweight
  • < 30 kg/m2: obese

How does it relate to your health?

The BMI does have its limitations. For example, it cannot differentiate between muscle fat and body fat. Further, it does not conclusively lead to disease (there is just high correlation).

It is not diagnostic, either. It just indicates your overall health and could inform decisions like whether weight loss surgery is right for you.

People in ‘normal’ and ‘overweight’ have similar risks for weight-related health issues. However, once you are considered obese, you run a much higher likelihood for the following conditions:

  • High blood pressure
  • Type-2 diabetes
  • Coronary heart issues
  • Stroke
  • Gallbladder disease
  • Sleep apnea
  • Certain forms for cancer
  • General body pain
  • Increased risk of mortality (death)

What about calculating BMI with children?

BMI is different with children than it is with adults. It’s calculated the same way, but the categorization is based on percentiles as opposed to predetermined ranges.

For children, being under the 5th percentile is underweight. Overweight is between the 85th and 95th percentile, and anything over the 95th percentile is considered obese.

What’s the BMI when gastric bypass surgery is needed?

The Mayo Clinic recommends gastric bypass surgery to be an option if your Body Mass Index is 40 or higher (which would be extreme, “morbidly obese”). If your BMI is between 30-39.9, then you should consider the surgery, too. This is especially true if you have weight-related health issues like type-2 diabetes, high blood pressure or hypertension.

Weight Wise is one of the most trusted bariatric surgery centers in Oklahoma. We have a team of surgeons, dietitians, providers and advocates that can turn people’s lives around. We offer free weight loss seminars for those looking to find out more information.