Your body will get used to it, if you give it time. While true that there is little direct scientific evidence, there is much science based evidence of symptoms caused by lack of water.
http://authoritynutrition.com/7-health-benefits-of-water/
Yes, I do know that waiting until thirst is felt means dehydration has already begun.
FWIW I quit drinking all sodas even diet soda, and drink only seltzer for thirst quenching. Seems to work.
What about drinking a glass of water before meals to limit food consumption? Real question.