Water

We've all heard that we should drink 8 glasses of water per day, but is that true?  There's actually  no scientific data to back up that particular number.  Water is important to health, but how much you actually need depends upon many things. A good rule of thumb is that you need 1/2 cup (4oz, 118ml) for every 100 kilocalories that you eat.  I need about 2000 kcals per day, so my total fluid requirement is about 10 cups.

But that doesn't mean 10 cups of water.  Milk, juice, tea and coffee are nearly completely water.  Yes, I know you've been told that caffeinated drinks don't "count".  Recent research shows that you may have to pee sooner, but you don't actually pee more than if there's not caffeine.  Also fruits and vegetables are 90% water.  With this Fruit & Veggie Challenge at work, I've been eating 3-4 cups a day.  That's easily 3 cups of my 10. 

You may need more fluid intake than average if:

• you exercise vigerously (losses in sweat and breathing)
• you live in a dry climate (evaporation)
• you eat a high protein / low carb diet (foods naturally low in water and need extra water for metabolism)
• the weather is hot (sweating)
• you drink alcohol (extra water needed for metabolism)

You've probably also read claims that drinking water will help you to lose weight.  It won't rev up your metabolism (as frequently claimed) but may help for the following reasons:

• Drinking water instead of sugared drinks reduces your kcals by about 200 per glass.
• The volume of the water may make you feel fuller and thus you may eat less.
• Many people mistake the way they feel when they are thirsty and think they are hungry...feeding the thirst cue adds unneccessary kcals.
• Drinking lots of water requires lots of walks to the loo.  When it comes to exercise...every step counts.

Water Calculation Source:  Whitney & Rolfe's "Understanding Nutrition"