Weight Loss and Calculating Body Mass Index

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BMI, or Body Mass Index is a rough assessment of a person's weight compared to height. While this is used widely as an indicator of just how much fat tissue is present in a particular body, it is not always an accurate assessment of a person's complete weight loss picture. There may be a better way.

Problems with BMI Calculations

While the BMI equation is very popular, the results from this equation can be grossly inaccurate and misleading. This may cause some folks to get the wrong idea about just how much weight loss is needed in a particular situation. An accurate baseline is needed in order to lose weight successfully and the BMI may not provide this baseline.

The BMI equation does not consider the particular specifics of a person's body composition. In other words, if person A works out and has more muscle, the BMI equation has no way of distinguishing what is fat and what is muscle. Older folks, or those with a low amount of body muscle may also get an inaccurate reading and thus be considered healthy. BMI measures body mass only.

Estimating Weight Loss Through Body Composition

Muscle is a good thing because it makes a body look better, and it burns more calories than fat tissue. More muscle means more calories burned and that is a great thing for someone trying to lose weight. Because the BMI does not provide an accurate assessment of total body fat, there are other ways to determine the correct amount of weight to be lost.

Weighing on a scale is not the best way because there can be daily fluctuations of weight levels. The mirror may actually be the best way to determine how much weight loss needs to occur and from where. Take a close look in the mirror without being overly critical. Think of it as a broad brush approach to weight loss. Find the biggest problem area first and start there. Don't get all caught up in the details and minor areas. Broad brush strokes.

Correct Measurement of Body Fat Percentage for Optimal Weight Loss

Perhaps the most accurate method to find out the actual percentage of body fat and muscle tissue is to be weighed while in water using hydrostatic testing. The process begins with a person sitting in a seat that is attached to a scale hanging over the water. The subject first weighed on the scale to determine a baseline weight. Next the person then submerged in the water and weighed once again. Fat is lighter than water, muscle heavier. The two weights are combined and a proper body fat percentage is determined.

There are other methods for determining BMI like bioelectrical impedance analysis which runs a tiny bit of electricity through the body to measure the resistance levels of fat and muscle. Skinfold measurements is another low–tech method which uses a special set of calipers to measure subcutaneous fat. None of these methods will provide a reading as accurate as hydrostatic testing. Obtaining an accurate assessment of lean body mass compared to fat body mass is an important first step on the road to successful weight loss.