http://www.madsci.org/posts/archives/may2000/958588306.An.r.html

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.

and of course:
http://en.wikipedia.org/wiki/Body_water

This body water is distributed in different compartments in the body. Lean muscle tissue contains about 75% water. Blood contains 83% water, body fat contains 25% water and bone has 22% water.

AND GET THIS:

Bioelectrical impedance analysis

Another method of determining total body water percentage (TBW%) is via Bioelectrical Impedance Analysis (BIA). In the traditional BIA method, a person lies on a cot and spot electrodes are placed on the hands and bare feet. Electrolyte gel is applied first, and then a current of 50 kHz is introduced. BIA has emerged as a promising technique because of its simplicity, low cost, high reproducibility and noninvasiveness. BIA prediction equations can be either generalized or population-specific, allowing this method to be potentially very accurate. Selecting the appropriate equation is important to determining the quality of the results.

For clinical purposes, scientists are developing a multi-frequency BIA method that may further improve the method’s ability to predict a person’s hydration level. New segmental BIA equipment that uses more electrodes may lead to more precise measurements of specific parts of the body.

Dope extended paper on BIA:
http://www.espen.org/education/documents/BIA1.pdf

From this epic FAQ:
http://www.faqs.org/nutrition/Smi-Z/Water.html

Physically active individuals generally have more water in their bodies than those who are less physically active. Because they sweat more, active people need to replenish water more often, thus raising their water level. A trained male runner may have up to 71 percent water in his body, while a female gymnast may have 70 percent. Obese individuals, on the other hand, have a lower percentage of water in their bodies (about 48%). Morbidly obese individuals are only about 36 percent water. In addition, the older one gets, the less water is retained in one’s cells. As a result, old skin looks drier and wrinkles appear.

Recommendations

The most efficient way for the body to get water is for a person to drink water. It is recommended that an adult drink eight to ten eight-ounce glasses of water a day. Athletes and active teens should drink at least ten to twelve glasses of water daily. However, many foods and beverages contain water, which can make up part of this daily intake. Fresh fruits and vegetables, cooked vegetables, canned and frozen fruits, soups, stews, juices, and milk are all sources of water. Most fruits and vegetables contain up to 90 percent water, while meats and cheeses contain at least 50 percent. Metabolic processes in the human body generate about 2.5 liters of water daily.

The only paper I’ve found so far on the relative body water percentages in various mammals—I’m trying to get a sense of whether human beings have a higher or lower body water percentage compared to other critters.

http://www.jbc.org/cgi/reprint/158/3/685.pdf

http://en.wikipedia.org/wiki/Water#Electrical_conductivity

Electrical conductivity

Pure water has a low electrical conductivity, but this increases significantly upon solvation of a small amount of ionic material water such as hydrogen chloride. Thus the risks of electrocution are much greater in water with the usual impurities not found in pure water. Any electrical properties observable in water are from the ions of mineral salts and carbon dioxide dissolved in it. Water does self-ionize where two water molecules become one hydroxide anion and one hydronium cation, but not enough to carry enough electric current to do any work or harm for most operations. In pure water, sensitive equipment can detect a very slight electrical conductivity of 0.055 µS/cm at 25 °C. Water can also be electrolyzed into oxygen and hydrogen gases but in the absence of dissolved ions this is a very slow process, as very little current is conducted. While electrons are the primary charge carriers in water (and metals), in ice (and some other electrolytes), protons are the primary carriers (see proton conductor).

Which brings up back to drew hempel:
http://mothershiplanding.blogspot.com/

While training to leave the Matrix I had a very strict diet – No Salt! (fairies can’t touch salt is well. See CIA mind control scientist Dr. Andrija Puharich’s book Beyond Telepathy, 1975, for the potassium-sodium paranormal resistance model). My guidebook was Taoist Yoga: Alchemy and Immortality, a late 19th Century text translated by Ch’an scholar Charles Luk. According to Dr. Solomon H. Snyder this belief is verified: “It seems that sodium might be the ion that translated recognition of opiates at the recept into changes in cellular function…sodium ion reduced opiate-receptor binding of the agonist etorphine.” (p. 96, Brainstorming) I should have followed my teacher Chunyi Lin because when electro-magnetic forces began pushing me around the room I began to freak out! When I sat in full-louts the room would spin around me! (This corroborates Kurt Godel’s proof that time is an illusion due to the rotation of the universe described by Einstein’s theory of relativity but not experienced because consciousness is beyond spacetime). This is the beginning of true samadhi according to Cambridge Unversity philosophy Ph.D. Peter Kingsley but I didn’t discover his book In the Dark Places of Wisdom until several years later. When I stopped practicing and I starting researching, I found several books by Master Nan, Huai-Chin, an eighty year old Ch’an professor in Taiwan. I read all four books several times each. Master Nan explores the deep question of how there can be different levels of empty awareness or, to put it in Einsteinian terms, how light can be experienced differently based on the spacetime dimension of the observer.