What is BMI and how is it used?

BMI is a term that gets used quite a bit in discussions about weight, obesity and bariatric surgery. The term has been the source of a lot of confusion.
BMI is short for “Body Mass Index.” It is simply a number calculated from a person’s height and weight. The more a person weighs in relation to their height, the higher their BMl. The formula used to calculate BMI is weight divided by height squared, and it is usually calculated in kg/meter2. Most times the units are not listed but assumed. For example when you say, “BMI of 35,” it is assumed that you mean “35 kg/meter2.”