When you start an exercise program, no matter what the reason, you are often given plenty of advice from friends, family, trainers, group fitness instructors, doctors, etc. Out of the dozens of suggestions (all given with the intent to help out), perhaps the most common one is, “make sure you are drinking enough water.” This is a great piece of advice and though it is usually in reference to needing more water when you exercise, there are many more reasons to drink water than for just pure hydration sake.

There are so many residual benefits to being properly hydrated that many people tend to just pick one benefit and stick to that as their reason to drink water. However, we would be doing proper hydration an immense disservice by not talking about all of the benefits it has on the body — especially the effect water has on aiding weight loss.

Many of the benefits discussed below are related to any fluid that hydrates the body, but it’s important to realize that the effects are most apparent with plain water (not to mention its lack of negative side effects that many other fluids can have on health). With that in mind, the following information focuses on water’s effect on the body’s functions.

To fully understand why water helps you lose fat weight, we have to understand every aspect of your body that water has an effect on because it is the combination of these effects that help you to lose weight.

What Drinking Ice Cold Water Does to the Body:
The most direct way that water helps increase calorie burn and weight loss lies in the way your body absorbs water. The body must first warm (or cool) fluids that enter the body to 98.6°F (body temperature) before they can be utilized. This process requires energy (calories) to either create heat (if drinking something below body temperature) or remove heat (when drinking something above body temperature). The calories required to do this are not a lot, but over time it can make a big difference.

The following example is specific to cold fluids but the effect of hot fluids is the same though the numbers are slightly different.

You burn roughly one calorie for every fluid ounce of water you drink, but this only counts if the water is extremely cold. Lets say you drink a liter of ice cold water - that is an extra 32 calories burned without doing any extra physical activity. That does not sound like much but keep this in mind; if you drink only one liter of ice-cold water everyday that is an extra expenditure of 224 calories per week, 896 calories per month and 10,752 per year - that is equal to 3 pounds of fat that you will have lost (or at least not gained) by simply drinking cold water. Though every individual has varying hydration needs, it is likely that you need a lot more than just one liter of water per day (particularly if you are physically active), so these numbers could easily be more impressive if you just increased your intake. How easy is that! Now keep in mind that this is just the first and most direct effect water has on the body. In actuality, being properly hydrated can have an even more significant effect on calorie burn.

Hydration's Effect on Physical Ability:
One of the most important ways your level of hydration affects your caloric burn is in relation to your ability to perform physical activity. You may know that you need to drink water when you exercise but do you know why? Lean muscle in the human body is made up of around 80% water and it needs that water to function properly. When you start to become dehydrated your muscle tissue starts to lose water and it makes it harder for that muscle to contract effectively, reducing your strength and endurance. It has been stated that as little as a 1% drop from optimal hydration can reduce your physical ability by up to 5%. You could actually see your caloric burn from your workouts drop by 5%, not to mention that you will feel weaker and less capable, which can slow your exercise progress in many ways.

For example, lets say you burn an average of 300 calories per day from your workouts; that would be a 15 calorie per day loss of potential expenditure. That’s 105 calories per week, 420 calories per month and 5,040 calories per year. That is equivalent to 2 pounds of fat content that you could have lost - double or triple those figures if you are even more dehydrated or if you burn more than 300 calories per workout.

The Effect of Hydration on Overall Metabolism:
This section could be easily expanded into a textbook of information of how and why water is used in almost every bodily function. To name just a few, it is responsible for absorbing and transporting all but four vitamins, storing carbohydrate in your liver and muscle tissue, aiding digestion, transporting and removing waste products in the blood, keeping your immune system functioning properly, and so much more. To save you from a very dry and science heavy read I will just say this; without optimal water levels arguably every function of your body would be negatively affected in some way.

Your basal metabolism is the amount of calories your body needs just to stay alive – it’s the energy needed to keep the body functioning, with absolutely no activity factored in. It fluctuates drastically from person to person.

For example, a woman who is 5 foot 4 inches tall and weighs 110 lbs can have a BMR (basal metabolic rate) of 1300 calories per day whereas a man that is 6 feet tall and weighs 200 lbs can have a BMR of 2015 calories per day (or more, largely depending on the amount of muscle tissue they have). If you use the same 5% drop in calorie burn when you are consistently only 1% below your optimal hydration levels you could see any where from a 65 – 100 calorie drop in your metabolism per day. That is a drop of 455-705 calories per week, 1,820-2,820 per month, 21,840-33,840 calories per year. That is anywhere from 6.24-10.5 lbs of fat per year that you could have lost or at least kept from gaining.

When you look at each one of these segments as individual scenarios the figures may not look very impressive but when you tally it all together it becomes clear that hydration can have a significant impact on weight loss efforts. If you take the above yearlong totals of the effects of staying hydrated as well as drinking ice-cold water you get a more substantial result. Over a years time you can lose anywhere from 11.24 – 15.5 lbs from simple, proper hydration. No extra exercise, no real extra effort, no supplements or pills, just drinking plain water.

People who already keep themselves well hydrated may not see quite as drastic of results but many people may see even more drastic results, all from a few extra glasses of water a day.

You should look at proper hydration (especially combined with working out) as the world’s most effective, least expensive, and virtually side effect free weight loss supplement. Whether you are trying to lose fat weight or just keep it off, you cannot afford to overlook the benefits of the most under appreciated fluid there is — water.