We all know that excessive weight causes obesity. However, it is not just weight itself but the type of weight that makes obesity a concern. Body weight can be sub-divided into three categories:  bone, lean body mass (think water and muscle) and fat mass. In most people, bone and lean body mass are fairly stable. Interestingly, about 18% of people are overweight, not due to increased fat mass, but rather due to increased muscle mass resulting from weight training. Increased fat mass is typically the cause of obesity. The body converts excess nutrients into fat and stores this fat for future use. As a result, fat mass can change dramatically (relative to bone and lean body mass) depending on the body’s energy requirements.

Obesity from excessive fat can be a primary or contributing factor to many human diseases. Fat has been linked to fatty liver disease and to cardiovascular disease through its buildup on the arterial walls, blocking blood flow. Obesity can cause reduced lung function by limiting the expansion of the lungs and can cause early arthritis due to a consistent overstressing of weight bearing joints.

Monitoring and maintaining body fat mass can help reduce body weight, reduce obesity related health complications, and increase wellness. Body fat mass can be measured using multiple techniques. However, the measurement is typically presented as body fat percentage which is the ratio of fat weight to total body weight multiplied by 100. A classic method of measuring body fat percentage is using calipers to measure skin folds. Another method is to send a small electrical current through the body. A more robust and more expensive method is the DXA (dual-energy x-ray absorptiometry) scan. It provides both overall body fat % and regional (abdomen, arm, leg, etc) fat %. 

For a simple and free method, use circumferential measurements and the LEVL body fat calculator to determine approximate body fat percentage. For men, the circumference of the neck and abdomen are required. For women, the circumference of the neck, waist and hips are required.  These measurements are used to calculate body fat percentage using relationships developed by the United States Naval Health Research Center.