As overweight and obesity has become more and more epidemic, particularly in the United States, tools that assist in weight control have become more prevalent. A method used in weight control that has become particularly popular in recent times is the Body Mass Index, or BMI for short. The Body Mass Index is, to put it simply, a means for determining a person's ideal body weight.

Though the Body Mass Index has become widely familiar over the last decade or so, the notion of using an index to determine ideal body weight has been in existence for over one hundred years. In the nineteenth century, a statistician from Belgium devised a mathematical formula for measuring obesity. The statistician's name was Adolphe Quetelet and the formula he devised to measure obesity was, appropriately enough, called the Quetelet Index of Obesity. The Body Mass Index is, for all intents and purposes, an updated description of the Quetelet Index of Obesity.

The Body Mass Index, or the Quetelet Index of Obesity, uses a mathematical formula to determine a healthy weight. BMI doesn't just measure overweight, but provides classification for exceedingly low body weight as well. An individual's body weight divided by the square of their height is the formula BMI uses to measure body weight health.

The BMI became popular in medical circles during the 1980's. Before this, a person's height was the single criterion used for determining an appropriate weight range. The problem with this sort of measurement was that it was too narrow in its consideration of a person's body composition, and didn't offer enough information about a person's physical make up and where he or she stood in relation to ideal body weight.

The Body Mass Index gave a thorough consideration of body make up by providing weight ranges, from healthy to unhealthy, and the BMI came to be the standard measure for obesity during the 80's. In the 1990's, as issues of overweight became more significant, US government efforts to encourage better health resulted in Body Mass Index discussion on a much wider scale, and beyond the medical profession.

Today, so-called Body Mass Index calculators are widely available on the web. Virtually anyone can now plug in their height and weight measurements and get a BMI weight composition reading. The problem with the widespread use of BMI as some form of authority for body health is that BMI is and always was meant to be used as a way of classifying body components of people with extreme weights, particularly obese persons. In other words, BMI was essentially developed to categorize the bodies of obese people, and expanding its use beyond this original intent and expecting perfect results is not particularly realistic.