A fitness assessment is performed by a professional trainer before you start your exercise program. One of the critical measurements taken is your Waist-to-Hip Ratio (waist measurement divided by hip measurement). This measurement is important because there is a correlation between chronic diseases and abdominal fat. A ratio above .80 for females and above .95 for males could put you at risk for a number of diseases, including cancer.
For example, if your waist is 31 inches and your hips are 41 inches, your Waist-to-Hip Ratio would be .76. Some people who consider themselves to be "skinny" could really be "skinny-fat", which is a skinny person with too much body fat. A "skinny-fat" person could have an unfavorable Waist-to-Hip Ratio. The lesson? Everyone needs to know their Waist-to-Hip Ratio.
Many people are confused about what Body Mass Index (BMI) means as it relates to body fat. Keep in mind that it is just one tool to use when you are looking at your health. Scientists use BMI as a research tool to make objective comparisons as to how fat a person is. A person with a BMI of 25 or above is considered overweight and a BMI over 30 is considered obese.
BMI uses your height and body weight to measure your fatness. This method has some limitations because it doesn't consider your body type (slim, muscular, etc.) For example, a fit person with high muscle mass will tend to have a high BMI which suggests that the person is overfat. This person would actually be fit and healthy with low risk for fat-related diseases.
So, even though you might use BMI as a starting point, your level of fatness is best measured using a direct method. Two methods used are under-water weighing and skinfold measurements. Under-water weighing is not readily available to most people. Having a skinfold body fat test with calipers done by a fitness professional is convenient and reasonably accurate.
A DIRECT BODY FAT MEASUREMENT WILL ALSO TELL YOU WHERE YOU ARE FAT! MANY PEOPLE HAVE DANGEROUS EXCESS ABDOMINAL FAT!