I thought I'd weigh in on this water thing that is going around, the idea that you should drink 1/2 your weight in water in ounces every day. Of course I have to convert kilograms to pounds, then ounces to millilitres for this to make any sense to me. But I like maths, I can do it.
This would mean a slender model-type woman might need to drink about 6 or 7 cups of water a day - and I am very sure most drink a lot more than that - and one blogger that I follow is required to drink 17 cups a day, which seems like far too much. (And that person has other fluids on top of the 17 cups of pure water.)
I'm a bit worried about that amount. My husband's mother once made herself very ill drinking too much water (not sure of the details) by diluting her electrolytes too much or something. So I'd say don't do it if it makes you feel sick or dizzy. Your body needs water, but not so much you are diluting or peeing out a lot of essential nutrients and electrolytes.
The old standard was 8 cups a day and I've even heard a nutritionist say that that includes fluid you are getting from food - you don't need to actually drink 8 cups of water.
Of course humans are extremely adaptable and we can survive on very small amounts of water. That doesn't mean it's the healthiest. I'm not saying to stop drinking. And we are so out of tune with our bodies (many of us) that we don't realise we are thirsty.
At my current weight, if I use this rule I would have to drink about 11 cups a day. I consider it a win if I manage 6.
In summary, I have no idea how much people "should" drink. But I don't think a formula like the 1/2 body weight thing is a sensible way to go about it.