Water provides no calories, is inorganic and is critical to life. The body is about 50-70% water-i.e. about 40 to 54 kg of a 77kg man is water weight. Loss of only 20% of total body water may cause death. And even 2% of total body water loss may decrease body abilities to 50%. We can survive without food for about 30 days but we can survive without water for only 3 days.
This may be a very debatable topic. Many studies have done on this and have different opinions on how much water should we drink in a day. It is depends on person to person.
Everybody needs different amount of water and The factors on which it depends are:
(1) It depends on person’s body weight– A big body needs large amount of water to survive than a small body.
(2) Depends on physical activity– A person with high level of physical activities will need more water throughout the day.
(3) Depends on carbohydrate intake– More the carbs you intake, more the demands for water of your body. Studies show that to digest 1grm of carbs we need 4grm of water i.e. 4 times of carbohydrates.
(4) Age– age is also a big factor. Our thirst signal will delayed with age. So, we should drink water throughout the day without getting thirst signal.
(5) Environment– yes, this is really a big factor. We need more water in a heat environment than in a cold environment. However we must drink water even in a very cold environment.
BOTTOM LINE: There is not any fixed amount of water that we should drink. Everyone need different amount. We should drink water without getting thirst signal. We need more water after taking a carbs rich diet.
Does drinking more water will give you benefit:
Many studies show that drinking more water will help you in losing weight. According to a study, drinking 500ml of water can temporarily boost metabolism by 25-30%. It may be best to take cold water because your body burns more calories to heat that water.
Drinking water half an hour before meal can reduce the amount of calories intake.
Drinking water in a very huge amount can cause the body to loss sodium through urination.