One way to understand body composition is to divide your body into three basic parts - fat, bone and lean body mass.

Fat Mass is usually referred to as body fat percentage. This number tells you how much of your total body weight is actual fat. Observing change in body fat is the best way to measure "weight" loss.

Lean Mass is everything else that makes up your weight. It includes muscle, bones, organs, water, and all non-fatty tissues. One pound of muscle takes up much less space than one pound of fat. So, as you exercise consistently and build up strength, your total body weight may actually increase. This can be confusing (and sometimes scary), but you are gaining muscle, while maintaining or even losing fat. Gains in muscle mass will increase your metabolism, thus enabling you to burn more calories during every activity—even sitting!

There are no exercises you can do to speed up fat burn in any particular area. Cardio activity, utilizing large muscle groups, burns fat all over the body. So, don’t waste your time doing lots of crunches to lose the belly fat, or boxing to lose your arm jiggle.

Scientists ascertained that there are three specific body shapes:

The android, or apple shape, is common among men. Fat deposits on the middle section of the body, mostly on the abdomen.

The gynoid, or pear shape, is more common among women. Fat is deposited on the hips and bottom.

A third type of body shape, the ovoid, does not differentiate between men and women. Here we can speak of an overall general coverage of body fat.

Fat distribution is influenced by age, genetic inheritance, race, but to a greater extent by gender-specific hormones. They are responsible for the distribution of fat on certain areas of our bodies. Estrogens, for example, which are responsible for the typical female sexual characteristics, will influence fat deposit in the "pear" format. They deposit on the hips, thighs, and belly, while testosterone will "lead" fat mostly towards the stomach and upper body.