To work properly your body needs the fluids you drink and the water it extracts from the food you eat. Your digestive system, brain function, the biochemical reactions that go on throughout your body, the lubrication of your joints, the detoxification of your system and the regulation of your body temperature, all need water.
When you don't drink enough water you become dehydrated. The situation can be made worse if your diet contains too much salt or if you drink a lot of caffeinated drinks or your alcohol consumption is high. Dehydration leads to water retention. This happens when your body tries to defend your interests by retaining as much water as it can in order to keep everything working. The result? You become bloated and you put on weight. If you're overweight or obese, some of your extra weight will almost certainly be caused by water retention.
How much water should you drink?
How much water should you drink to avoid becoming dehydrated and to keep everything working efficiently? During a normal day you'll lose over 2 litres (3 / pints) of water through normal bodily functions – you lose a pint of water simply by exhaling. Some of this will be replaced by what your body extracts from the food you eat, but unless you replace what you lose – and then some – you'll become dehydrated. To avoid this happening, the simple rule is to keep your salt intake to no more than 6 grams a day, avoid caffeinated sodas, drink alcohol in moderation, and drink at least 7-8 medium glasses (a medium-sized glass = 8 fluid ounces / 200 ml) of water every day. The good news is that by simply following this rule you can get rid of bloating and lose the weight that comes with it.
The best thing to do is to start the day with a couple of glasses of water, and then spread the time you drink water throughout the day. If you drink a glass of water 30 minutes before you have a meal, it will help to reduce your appetite – and your calorie intake -maybe by up to 80 calories a day. That's over 8 pounds / 4 kilos in a year just by drinking the right amount of water. Do other drinks like tea and coffee count towards your overall fluid intake? Yes, they do, but it's best if you drink water in addition to any cups of tea or coffee you may have.
Be aware that the signal that you are hungry and the signal that you are thirsty are very similar and are often confused.
It's very easy to answer a thirst signal with food. The best thing to do is to always answer what you think might be a hunger signal with a glass of water. If it's a thirst signal it'll satisfy your thirst, if it really is a hunger signal it'll have reduced your appetite.