The advice to drink water is so common in dieting circles that you may be tempted to take it for granted. The fact is, drinking the right amount of water can be a powerful aid to your weight loss efforts. Water supports every system necessary for losing weight and keeping your metabolism running properly.

The bottom line is a conscious focus on water intake should be a part of ANY diet.

How Water Can Help You Lose Weight

One the very best reasons to drink a lot of water is because it replaces calories you drink. It's a great way to reduce calories. See the "Avoid Drinking Calories" page for more.

Another great reason: The intake of water causes the body to release several hormones into the body, in particular adrenaline and noradrenaline. These hormones put your body in an increased fat-burning mode for up to two hours after drinking water, a great boost to your weight loss efforts. Water is like free energy that actually burns calories!

Here are more reasons why water can help you lose:

Low carb diets can cause the body to drop water as it burns through glycogen stores, so you need more fluid to prevent dehydration
Cold water helps you burn extra calories because it ever so slightly lowers your internal body temperature; your body expends energy (burns calories) to warm back up
Some scientists even believe the body can use water like a type of energy (more info below)

Does water reduce hunger?

Some studies show the effect, others don't. Water consumed by itself tends to be absorbed very quickly so it doesn't have a long term effect. The exception might be for older individuals where research shows water has a good satiating effect (this is likely because stomach emptying slows down as we get older, which means water stays in the stomach longer.)

However, water does have an immediate hunger blunting effect due to the sheer weight and volume of it (see Calorie Density theory). So we could logically assume that even if water is absorbed and eliminated quickly, we can counteract that problem by simply drinking more of it (or alternatives)!

How Much To Drink Each Day

This varies according to climate, activity, diet and other factors. In hot temperatures, or if you're exercising, you'll need more. If you're eating a lot of fiber or protein, you'll need more water than usual. On the ketogenic diet, you'll also need more water.

So there isn't a one-size-fits all amount, but there are some general guidelines to follow. Generally speaking, people don't drink enough.

Here's An Easy Rule: Divide your weight in half; that's how many ounces of water to drink per day.

Formula Format:
(Your Weight In Pounds) / 2 = Daily Ounces of Water

Example: If you weigh 180 pounds, you should aim for around 90 ounces a day.

Water content of food and other drinks counts toward your total. An average person gets about 20% of the average person's daily water intake. But if you are eating low-calorie dense foods (which have high water content), you might be getting closer to 50% or more just from food so you could get away with drinking less water directly.

Recommendations aside, drink water anytime you feel thirsty. If you feel thirsty enough to drink more than the amount you calculated, be sure to do so. As long as you aren't going overboard, there's no harm in drinking a lot of water.

On the other hand, if you're overwhelmed with the amount of recommended water and just can't do it, don't worry about it. Your body probably knows best and maybe you don't need it. Or you may choose water alternatives as a way to increase overall water intake.

Other factors:

Outside and indoor temperatures. You'll need to drink more when it's warmer. During winter and if you aren't getting much physical activity, you might not need as much water.
Physical activity. Especially combined with summer temperatures, you should dramatically increase water intake.

Guidelines: When to Drink

Most people simply do not drink enough water. You can drink a lot of water by spreading it out over the course of a day.

Here is a good schedule:

Take two glasses of water as soon as you wake up to make up for the water lost during the night. This will rejuvenate your body and put you into immediate fat-burning mode to give you a great jump start to the day.
Drink a glass or two of water half an hour before every meal. This will help prevent overeating and minimize any problems with indigestion. (See more on the Pre-Fill page).
Drink a glass or two of water between meals to energize you and prevent false hunger sensations. Aim for roughly 2 hours after a meal (that's when most carbs have been digested and your blood sugar begins to lower).
Always drink a glass or two of water before physical activity, such as going for a walk, or any other activity that might cause sweating.

Water-Hunger Rule: Every time you start to feel hungry, or get a craving, immediately drink one or two glasses of water. Wait fifteen minutes to see if the so-called hunger goes away. If it doesn't, you can feel free to eat, preferably a high-protein snack. But most importantly, don't wait until you feel hungry or thirsty to drink water. Be proactive and drink your water continually as a matter of habit.

Have a Bottle of Water Nearby: Buy a sports bottle and keep it with you. Or carry around a water bottle. That's typically the only way most people can drink as much as they should (or intend to). If you have to walk to a fountain or tap to get a drink, chances are you won't do it until you're really thirsty and your overall intake will go down. Having a bottle nearby is also a way to visually monitor how much you are really drinking.

Plain Water Alternatives

Pure water is the best substance for satisfying real thirst. If your mouth is dry, if you feel thirsty -- drink WATER first! That's what your body wants. That's what satisfies thirst the best. Avoid the habit of reaching for other drinks when you are thirsty -- even zero calorie sodas.

That said, other liquids can increase your overall intake of water. And if you simply cannot stomach plain water, then alternatives are better than nothing.

For better tasting water:

Bottled water (try different brands)
Squeeze some lemon juice into water (add the juice from half a lemon to warm or cold water and drink immediately upon waking)
Add a splash of orange, grapefruit, cranberry or tropical juice (just enough to flavor it)
Flavored bottled water (calorie free versions)
Zero-calorie powders like Crystal Light

Low or zero calorie options:

Milk: Fat free or 1% best. Although it contains calories, they are good calories because of the protein which is filling. Plus you need the calcium (helps with weight loss!), Vitamin D and other nutrients.
Diet sodas. A good way to save calories over regular soda if you feel like you cannot give up your soda drink. (However, see "Avoid Drinking Calories" for additional considerations regarding diet soda)
Coffee: Plain, or sweetened with a low calorie sweetener. A splash of fat-free milk adds creaminess for just a few more calories.
Iced Tea: Not the bottled or canned kind. Make your own with a small amount of sugar or Stevia; add flavor with lemon or lime wedges.

None of the above are pure water substitutes, but they do boost hydration without adding many (or no) calories.

Note: On strict low calorie diets, sometimes a dieter will swear that drinks with artificial sweeteners have stalled their weight loss. Even though it may not make sense, certain diets can be finicky that way.

Bad or inferior alternatives:

All sugary drinks including sodas and bottled fruit drinks
Regular sodas, colas, etc
Alcohol
Fruit juice

All of the above can be a hindrance to losing weight due to the high sugar and calories. See Avoid Drinking Calories for more on this topic.

Are You Dehydrated?

Don't assume you are drinking enough water.

Even if you feel like you drink a lot of water every day, there's a chance that you are still dehydrated without knowing it. That's because most people are unable to recognize when they are truly thirsty.

The biggest mistake people make is waiting until they get a dry mouth or throat before taking a drink. Unfortunately, a dry mouth is actually a very late sign of dehydration. When your body starts losing water, one of the first things that happens is that your saliva glands increase their output to ensure that you can still chew. The increase in saliva delays the drying of your mouth, so that by the time your mouth becomes dry, you have already lost a significant amount of water. Most of the lost water, around 66%, comes from inside your cells, 26% comes from the environment around the cells, and only 8% comes from your blood. So even a blood test would not show that you are dehydrated until late in the game. Your saliva glands will start to dry up eventually, but by then you're in a serious state of dehydration.

If you are over 50, matters are even worse. Scientific studies have shown that your ability to detect thirst starts to decrease at around age 50 and continues to decrease as you get older. One study demonstrated that elderly people couldn't tell that they were thirsty and needed water even after a full 24 hours without a single drop of water.

There are a few other signs that can indicate a state of dehydration. Headache is a common sign, although headache can be caused by other things, too. One of the more reliable signs is the color of your urine. If it's consistently clear or lightly colored, then you're probably getting enough water. If it's consistently yellow, that means you're starting to get dehydrated and need to drink more water. If it's orange, you're already in deep trouble and need to take action immediately. Sadly, both headache and yellow or orange urine mean your cells are already dehydrated, and you needed to drink more water hours ago. You probably felt some signs of thirst back then without even recognizing them.

Are You Hungry ... or Thirsty?

It's surprising, but many people can mistake thirst for hunger. Some experts don't agree -- so there could be some individual variation with this theory. However, when you're trying to cut calories you need to account for this possibility.

There are three different forces that are at work that may explain why you feel like eating, when what you really need is water.

First, when the brain starts to get low on energy, it immediately sends out signals. Since the brain is a major user of sugar for fuel, these signals often take the form of sugar cravings. But the brain can use water for energy as well, through a process scientists call a "cation pump" that creates a form of electricity within cells. This type of energy is especially efficient in nerve and brain cells, as you might imagine. The simple act of drinking a glass or two of water is enough to fuel this process and can often stop the supposed hunger pains in their tracks.

Second, early signs of indigestion are frequently mistaken for hunger pains. Eating food only causes the indigestion to flare up even worse, resulting in gas, bloating, and heartburn. On the other hand, drinking water immediately will often relieve the symptoms right away.

Third, the brain doesn't even distinguish between thirst and hunger in most cases. The body's hunger and thirst sensations are controlled by the same area of the hypothalamus. For this reason, feelings of hunger and thirst often occur at the exact same time, even when all the body needs at the moment is water. Considering what we know of the brain's energy sources, this shouldn't be too surprising. Often the brain's needs can be met by either water or sugar equally well, so in a sense it doesn't care whether you provide that energy by eating or drinking. But water is the most efficient source of energy in these cases. Water is absorbed quickly and reaches the brain in a matter of minutes. Whereas food--even if it's pure sugar--takes longer to be digested, converted to glucose, and transported through the blood stream to the brain. On top of that, the food you eat often provides extra calories and fat that you didn't even need.

That last sentence is the true clincher. Regardless of the cause, if you mistake thirst for hunger and eat a snack or meal instead of drinking water, you're getting excess calories that you didn't need. If you eat starchy or sugary foods to satisfy what you thought was hunger, you're probably just making matters even worse. You might get a spike of energy, but you also get the accompanying crash that causes more cravings and overeating.

The solution to all this is to follow the guidelines we've already provided above.