Unhealthy Healthy Habits

I was going through Msn Health And Fitness where I read about 'healthy habits' which aren't really healthy. And I came across this:

Drinking eight glasses of water a day
Admit it, this is one healthy habit that’s a royal pain. Luckily, it’s also completely unnecessary. For some people, eight glasses a day might actually be far too much, leading to sodium deficiencies and potentially life-threatening water intoxication, caused by kidneys not being able to keep up the intake of liquids. In 2002, a kidney specialist tried, in vain, to find any scientific evidence supporting the eight-glasses-a-day myth. His report, published in the American Journal of Physiology, concluded that this standard health advice was complete and utter bunk that, like many urban legends, stemmed from a tiny grain of truth. Apparently, the dietary guidelines provided by the Food and Nutrition Board of the National Research Council do say that humans need 1 milliliter of water for each calorie of food—adding up to about 10 cups a day. However, the same guidelines also say that we get most of this liquid from the water in solid food. There’s no need to drink more.
Source: Msn Health and Fitness

So do I stop drinking a lot of water, or do I first ask my kidney?

And, another one I read about was : Carrots improving your eyesight.

Apparently, During World War 2, the british navy fighters were spotting Nazi pilots from further distances and shooting them down. So what do they do? They spread the news that carrots were helping their pilots see in the dark. What really happened was, the british developed a better radar system that they didn't want their enemies to know about.

Carrots are a good source of Vitamin A, but eating a lot won't give you night vision ... instead, it'll develop a toxin in your body, which isn't fatal, but hey... Toxin.