Determining Body Fat Percentage

My brother asked me today about how to measure his body fat.
There is no one accepted best way to measure a person's body fat. Several ways have been described and there are commercially available tools. The oldest described method uses calipers to measure the thickness of skin fold at predetermined areas of the body - arms, abs, and thighs. With your height, weight, age, sex, and race, these numbers are entered in to a formula, to produce your body fat. Another method is to compare how much a person weighs in air versus in water. The same demographic data and another formula produce the body fat. This method is often thought to be more accurate than using calipers. This is as close to the gold standard that we have. College, professional, and elite amateurs often have their body fat measured by this method. This method is not available commonly. The only other place I have seen this done is at university physical therapy departments. I have never seen this done. The third method is called the US Navy Method. The circumference of our neck and abdomen is measured using a tape measure. Then another formula is used. None are proven to be more accurate than others, so I recommend that at least the third method be used. People will have a number to follow. I think this is important because we all should try remain healthy by watching what we eat and getting enough exercise. The body fat, when it is out of range, is a simple warning signal that better preventative care for your health should be done.