Fat mass + Bone mass + Muscle mass = 100% of the body composition
As there is water in muscle and fat, the water mass cannot be added to the other metrics when calculating the body composition.
Total body water is the total amount of fluid in the body. It includes the intracellular water and the extracellular water that represents the amount of water contained in both the cells and the tissues.
For example, body fat contains approximately 10% water, while muscle is approximately 75% water.
The normal ranges for water mass are as follows:
Body fat is made up of tissue that contains fat cells. Body fat tends to accumulate on the hips and thighs (known as gynoid obesity) in women, and around the stomach (known as android obesity) in men.
Fat mass is the opposite of lean body mass, which is made up of muscles, internal organs and bones.
The normal ranges for fat mass are as follows:
Muscle mass indicates the weight of muscle in your body. Muscle mass is composed of 3 types of muscles: skeletal, smooth, and cardiac muscle.
Skeletal muscle is also called striated muscle and is under voluntary control. As an example: the biceps are a skeletal muscle.
Smooth muscle is an involuntary non striated-muscle that contracts autonomously without any voluntary thought. The gut is an example of a smooth muscle.
Cardiac muscle is a mix between skeletal and smooth muscle: it is an involuntary striated muscle.
The normal ranges for muscle mass are as follows:
Bone mass is the weight of bones you have in your body.
The normal ranges for bone mass are as follows: