What Is BMI?

Your Health, Your Hospital

BMI, the short for body mass index is a ratio between weight and height used as a measure of body fat for adult women and men. BMI is a quick and relatively reliable tool to determine whether a person’s weight is low, normal or too high, but it does not actually calculate body fat percentage.

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Health Risks Associated With Obesity in Adults

A BMI value over 30 is a warning sign that changes need to be implemented in order to regain a better quality of life. If regular diet and exercise do not lead to optimal weight loss, and especially if obesity-related health conditions are present too, it is for a medical professional to determine the proper approach to weight loss. Life-altering health conditions associated with obesity usually affect vital organs and include:

  • High blood pressure or hypertension
  • Type 2 diabetes
  • Heart conditions, such as coronary heart disease, stroke
  • Respiratory conditions among which sleep apnea is the most common one
  • Certain types of cancer such as breast and colon cancer

According to several studies, weight loss improves obesity-related health conditions and overall health. In the light of all this, it is recommended for overweight or obese people to focus on losing weight.

BMI Categories

Because different nations have different body builds and varying nutritional habits, different countries use different values of BMI to differentiate between weight categories. BMI categories used in the United States are as follows:

  • BMI under 18.5 indicates underweight
  • BMI between 1.8 and 25 indicates normal weight
  • BMI between 25 and 30 indicates overweight
  • BMI between 30 and 40 indicates obesity
  • BMI over 40 indicates morbid obesity

Whenever calculating a BMI value, the fact that BMI does not differentiate between body fat and lean muscle mass must be taken into account. People with an athletic build and a rather large muscle mass might come out as overweight if strictly BMI is considered as body fat measure. Similarly, people with a light bone structure might come out as being of normal weight, even if they have accumulated body fat.