A lot of people are obsessed with their body fat percentage. Many more, while not obsessed, pay close attention to this number, even more than they do to their weight on the scale. Why is that? Why do people care so much about this particular number? If you're interested in fitness, or even just in looking hot, this percentage is important. Here's why.

Knowing your height and weight isn't enough to tell you if you are fit. Imagine two guys. They are both 5'10" and weigh 210 pounds. If height and weight were all that mattered, we would say that both of these guys are sadly out of shape. And one of them is. He's Joe, a 50-year old computer programmer who hasn't worked out in decades. He has skinny arms, spindly legs, and a beer gut.

Now the other guy, Dave, is a running back for a college football team. He has bulging muscles, incredible strength and speed, and not an ounce of fat on him. Clearly Joe and Dave are about as far apart as you can get in terms of fitness, yet they are both the same height and weight.

If we had measured their body fat percentages, we would have gotten very different results. Joe the computer guy probably has around 30% fat on his frame, while Dave is probably at less than 10%. This number is definitely a better indicator of overall fitness than height and weight.

It also plays a big part in your appearance. If your fat percentage is too high, you'll start to look soft and doughy. On the other hand, if you get the percentage down toward the bottom of the healthy range, your muscles and features will be well-defined, and you may even find yourself with a set of six-pack abs.

Your body fat percentage is also a factor in preventing illness. The human body needs some fat on it, but not too much. If you can keep your percentage in a healthy range, your body will work at its most efficient, and be much less susceptible to illness.

If you get too far over the ideal fat range, you end up with the condition called obesity. When you are obese, you have a far greater risk of major illnesses like heart disease and diabetes. If you get too far below the ideal fat range, you can develop a whole different set of medical problems, including interruption of a woman's menstrual cycle, and in extreme cases, death.

It's no wonder so many people are concerned with their body fat percentage, even obsessed with it. Your body fat percentage definitely does matter, and now you know why.