While it is interesting to know how much water, protein, fat, carbohydrate, and minerals are found in the body, it is often more helpful to take it up a level and look at the contributing tissue. In fact, the contribution of various tissues explains the relative contributions made by the different molecules and minerals.
Muscle and fat (adipose tissue) are typically the greatest contributors to body weight. For instance, a generally lean man will be about 40 to 45 percent muscle and 14 to 18 percent body fat. That means that muscle and fat make up half to about two-thirds of his body mass. For this man, bone might contribute about 8 percent and the skin 2 percent. The rest of body weight is composed of organs and tissue such as the heart, lungs, liver, kidneys, intestines, pancreas, brain, spinal cord, and our circulations (blood, lymphatic).