Although BMI is one tool that could be used in a weight loss program, it's not as accurate as a tape measure, or taking body fat measurements. The BMI doesn't take into account the body type of the individual. For instance, if you compare two 6' tall 225 pound guys they would have a BMI of 30.5, considered obese. What the BMI doesn't distinguish is one of the guys is a muscular athlete while the other is a pot bellied couch potato. If you use one of several ways to measure body fat, you would see the first guy has 10% body fat, while the couch potato would have 25% body fat.