Body composition varies according to gender and fitness level, because fatty tissue contains less water than lean tissue. The average adult male is about 60% water. The average adult woman is about 55% water because women naturally have more fatty tissue than men. Overweight men and women have more water, as a percent, than their leaner counterparts.
The percent of water depends on your hydration level. People feel thirsty when they have already lost around 2-3% of their body's water. Mental performance and physical coordination start to become impaired before thirst kicks in, typically around 1% dehydration.
Although liquid water is the most abundant molecule in the body, additional water is found in hydrated compounds. About 30-40% of the weight of the human body is the skeleton, but when the bound water is removed, either by chemical desiccation or heat, half the weight is lost.
Can You Drink Too Much Water?
Can You Drink Distilled Water?