Day 18D--Pencentages

I am a big fan of logic. Sadly, this causes me some problems when I encounter the art of medicine. Sometimes, they don't seem to use logic at all.

Take for example the idea that everyone should drink 8 glasses of water a day. This seems pretty simple and innocuous until you realize that a person who weighs 100 pounds is told to drink the same amount of water as someone who weighs 200 or even 300 pounds. Now the randomness of 8 glasses a day makes little sense. It turns out that the real number is 1/2 ounce of water for every pound of weight. Some of this water can come from other beverages and even foods. The figure of 8 glasses applies to a person who is about 125 pounds. I theorize that women who were dieting in the 1950s-1970s were the ones paying attention to the water intake, so the 8 glasses became the standard figure.

I'm starting to theorize that the lose 1-2 pounds a week figure comes from the same dieting demographic. I can't comprehend how my weight loss percentage should be less than 2% a week, but a person who weighs 200 pounds can only lose 1% a week. What if a severly obese person used the same gauge. It could take them several years to get to a healthy weight and they'd only be losing .5% per week. After much searching, I found a few places online that say it's 1% a week, but they aren't reliable sites and don't cite anything for their figure.

If any medical or fitness professionals have a reason for the 1-2 pounds figure or a percentage that should be followed for people of all weights, please let me know. I'm really curious and want to understand the science and logic of it.