>I would think one should only drink when they are thirsty.

We cannot trust our senses in the modern community where food is salty and
low in water and our bodies are more or less damaged from early age which
creates new needs for us. For those who stick to a western lifestyle there
are numerous interventions which may limit such damage. Hormone replacement
therapy, vitamin-D and lipid lowering statins are some of them. A high
intake of water may hypothetically be another example. In elderly
westerners its benefits seem rather convincing to me [Vellas B, Albarede
JL, Garry PJ (eds). Hydration and Aging. Springer, NY, 1998].

When I started eating unsalted "paleolithic" foods 11 years age I became
less thirsty and drank less than previously while urine volumes increased.
The latter is because the new diet is rich in water. Juice is not richer in
water than fresh fruit. Below is the average (standard deviation) water
content of some food groups in Sweden (g/kg).

Meat    709 (59)
Fish    743 (121)
Fruit   842 (50)
Tubers  851 (67)
Vegetabl.       886 (74)
Nuts    105 (152)
- excluding chestnut and coconut  48  (13)

Fats/oils       306 (250)
Cereals 200 (174)
Dairy pr.       643 (229)
Juice   846 (122)

Staffan Lindeberg, M.D. Ph.D.
Dept of Community Health Sciences, Lund University, Mailing address:
Primary Health Care Centre, Sjobo, S-22738 Sweden, +46 416 28140, Fax +46
416 18395 <[log in to unmask]>
http://www.panix.com/~paleodiet/lindeberg/