Nutrition / Hydration Calculators
Thought you may find these calculators interesting. Remember that this is based on a "normal" person's needs. We need more protein and water and less carbs, but I think it presents a pretty decent guideline for those further out.
http://nutrition.about.com/library/bl_nutrition_guide.htm
This one above .. gives you a calculator on how many carbs and calories to go by for maintaining and losing weight .
http://nutrition.about.com/library/blwatercalculator.htm
This one above - deals with how much water you should drink a day .