I’ve often heard that, when in a wintry survival situation, you should always melt snow and drink the resulting water rather than eat the snow directly (in order to quench your thirst). The reason given was always that your body had to heat up the snow and you risked hypothermia.
Not too long ago, I heard a more interesting reason: Not only does your body have to heat up the snow, but doing so uses up water–so that, even after you have eaten the snow, you wind up with a water deficit and are more dehydrated than before.
Any truth?
Inspired by the Catabolic diets thread.
http://boards.straightdope.com/sdmb/showthread.php?threadid=42356