Fat Math

Ever wonder if you are overweight, and want to get all scientific about it?

The thing that is done these days is calculation of your Body Mass Index. You take your weight, and divide it by your height squared. If you can use pounds and inches if you like, and then multiply the lot by 703. This is to align it with similar metric calculations.

For example, a person 5'10” who weighs 150 pounds comes in with a score of 21.5.

Sadly, this doesn't tell you anything about the person being fat or not.

Person One has an overall weight of 150, and also has a lower than typical amount of body fat, and more than the normal amount of muscle. Her percentage of body fat is a very athletic 10%. Absolutely not fat. This is Olympic athlete level. As stated earlier, her BMI is 21.5 , or normal.

Person Two is also 150, but is a bit of a slug, having significantly less muscle than average. Her body fat percentage is 33%, while her BMI says she's the same as our Olympic athlete. Her muscle mass and high fat level makes her clearly overweight by any standard. She almost scores as obese according to her fat level. With these numbers she may not look particularly overweight, but she is. Her BMI is also 21.5 , or normal.

Body fat percentage is by far the superior method of calculation, so of course, BMI is the more used scale. It's only advantage is that it's easy to figure out. The disadvantage is that it is pretty meaningless.

To measure body fat is harder, although getting easier all the time. There are even bathroom scales now that will use a tiny electric pulse to measure it for you.