While many recent studies indicate that drinking water can help you lose weight, a gallon of water may be excessive, depending on your current height, weight, age and gender. Too much water can actually give you dangerously low sodium levels, and your neurons need sodium to fire. On the other hand, dehydration can slow your metabolism, and drinking water before meals can help you feel full. Burning more calories than you consume is the only way to lose weight, and water is an important part of that process, but you have to drink it in moderation.

Water Before Meals

A 2010 study by Dr. Barbara Davy of Virginia Tech in Blacksburg, Virginia, found that drinking two glasses of water before meals helped participants lose five extra pounds over 12 weeks, in comparison with a control group that did not drink water before meals. In another study, the same researcher found that people who drank water before meals consume about 75 fewer calories per meal. In these cases, the water itself does not physically reduce your weight, but it does make you feel full, which keeps you from consuming as many calories, and consuming fewer calories is a key component of weight loss.

Dehydration

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According to CNN's diet and fitness expert Dr. Melina Jampolis, your metabolism slows down even if your body is just one percent dehydrated. Metabolism is a term for breaking down food into energy and using that energy to build new cellular components. This process requires energy, or calories, so if it's slow, you're burning fewer calories. About 60 percent of your body is made up of water, and water helps flush toxins and carry vital nutrients to your cells, so water is imperative for your overall health. Because it's so important, if you don't get enough water, your body will actually start holding on to whatever water it gets, which leads to water retention, or excess weight.

According to CNN's diet and fitness expert Dr. Melina Jampolis, your metabolism slows down even if your body is just one percent dehydrated.



Because it's so important, if you don't get enough water, your body will actually start holding on to whatever water it gets, which leads to water retention, or excess weight.

Water Loss and Proper Replacement

You may have heard the old adage that tells you to drink eight glasses of water a day. This is a good guideline, but appropriate water consumption isn't that simple. In fact, dieticians and scientists have differing theories about the right amount of water to drink, but their calculations generally come to roughly the same conclusions -- about eight 8-oz. glasses, or around two liters, which is roughly half a gallon. Your body loses about two to three liters of water per day through sweat and urination, so you need to replace that much. About 20 percent of your water comes from food, so you need to drink the rest. Men generally lose more water than women, but an athletic woman would need more water than a sedentary man. The best way to tell if you are consuming enough water is to ensure that your urine is clear or pale yellow and that you rarely feel thirsty.

You may have heard the old adage that tells you to drink eight glasses of water a day.



Your body loses about two to three liters of water per day through sweat and urination, so you need to replace that much.

Weight Loss Guidelines

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On its own, drinking water won't make you lose weight. Losing weight requires proper diet and exercise, because the only way to lose weight is to burn more calories than you consume. Aerobic exercise is a key component of this process, as it burns enough calories to get your body to start burning stored fat. In addition, it's also important to increase your overall activity, eat healthier foods such as lean protein and fresh vegetables, and make the process enjoyable so that you stick with it.