Re: What percentage of the human body is composed of water?

Different people have different percentages of their bodies made up of 
water. Babies have the most, being born at about 78%. By one year of age, 
that amound drops to about 65%. In adult men, about 60% of their bodies 
are water. However, fat tissue does not have as much water as lean tissue. 
In adult women, fat makes up more of the body than men, so they have about 
55% of thier bodies made of water. Fat men also have less water (as a 
percentage) than thin men.

So you can see three possible reasons for the discrepancies you have found:
1) Babies and kids have more water (as a percantage) than adults.
2) Women have less water than men (as a percentage).
3) Fat people have less water than thin people (as a percentage).

A forth reason is that different people measure per cent water a little 
differently, causing small differences in the answer.