How can drinking water help me lose weight?

Heidi Powell
Water plays a critical role if you’re trying to lose weight and/or achieve some health and fitness goals:
  • Drinking water can help you feel full. Often, when you feel hungry, your body is trying to tell you it’s thirsty.
  • Got cravings? Drink some water and usually that craving will go away. And since water has zero calories, think of all those calories you’ll be saving by drinking water instead of caving to your cravings!
  • Water energizes your muscles, which means your workouts will go better, your body will get stronger, and you’ll be able to burn more calories.
And don’t forget to drink water before, during and after exercise. You need to replace all that water you’re sweating away while your well-hydrated muscles are burning all those calories!

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Dr. Andrea Pennington, MD
Integrative Medicine
When we don't consume enough water, the body loses a valuable energy source. Water actually provides hydroelectric fuel for the brain and is used by all of our cells to perform vital functions. Most of us drink more coffee, juice or soda than plain water and we pay the price for it with obesity, high blood pressure and diabetes. Without water we cannot break down food into the elements needed to get into our cells nor can we extract the vitamins and minerals from our diet. So, water helps to produce energy in every way.

If you will drink one to two glasses of water one hour before meals, not only will you eat less food, but you'll actually absorb the nutrients in that food better so that your body is better energized.
Jill A. Grimes, MD
Family Medicine

Drinking water can help you lose weight because often we think we are hungry when we are really thirsty. Drink two 8-ounces glasses of water with breakfast, lunch, and dinner. Drinking a couple glasses of water with each meal will help you recognize what your body is really craving.

A study of obese adults showed that people who drank 16 ounces of water before each meal along with following a low calorie diet lost more than 4 pounds more than the group that simply followed the same low calorie diet.

Janis Jibrin, MS, RD
Nutrition & Dietetics
Staying hydrated will help you lose weight. Nutritionists and trainers always notice that their clients seem to lose weight more easily if they drink enough water, and now researchers from the University Medicine Berlin in Germany may have discovered why. Their studies show that drinking two cups of water raises metabolic rate (the rate at which your body burns calories) by about 30 percent. This effect peaks in about thirty minutes and disappears completely in about an hour. Researchers estimate that if you drink about six cups of water daily, you could, theoretically, burn an extra 48 calories a day, which could translate into a 5-pound weight loss for the year.

Other ways water may lower the number on your scale: it might help you eat a little less. We often mistake thirst for hunger; instead of filling up a glass with water, we turn to food. So stave off thirst, and you may shave off some calories. And going into your workout well-hydrated gives you more energy and endurance. You'll get the most out of your hour at the gym or your walk, burning more calories and increasing fitness.
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Manuel Villacorta
Nutrition & Dietetics
You've heard it a million times, but drinking water is essential for keeping energy up, aiding the metabolism, burning fat, and more. It's the fluid your body needs for life, and it's an instrumental part in your weight loss. Other fluids can be useful, but water is obviously the best choice as it is calorie free. Forget about that whole eight cups a day thing. I want you to relax and remember to have a healthy amount of water whenever you think of it. Thirst can confuse your sense of hunger so make sure you stay hydrated.
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Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
We all know that water is healthy, but what you may not know is that it could help you shed excess pounds. Each day, drink enough water so that your urine is clear. A recent study showed that your metabolic rate jumps within 10 minutes of drinking ice-cold water, and it stays up for an additional 30 minutes after you drink it. Research has also found that drinking an average of 6.5 cups of water per day helped people consume 200 fewer calories a day.
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Bob Greene
Bob Greene on behalf of The Best Life

Research shows that it might help you peel off pounds. In fact, people who drink an average of 6½ cups of water each day consume 200 fewer calories a day, according to a study from the University of North Carolina at Chapel Hill. Do the math: That's a loss of about 20 pounds a year. Experts aren't sure if the water itself helps quell appetite, but what is clear is that water-drinkers are healthier overall. They tend to have better eating habits and they drink less soda. Not to mention, drinking water can be distracting - you might be less likely to reach for chips if you have a tall glass of H2O in hand. In fact, many nutrition experts recommend drinking water when a craving first hits to delay - and potentially even prevent - an overeating episode. It's a good idea in general to hydrate whenever you feel the urge to eat just to make sure you're not confusing hunger for thirst.

Water is necessary for all physiological processes, including digestion and calorie-burning. It can also help make your workouts a little easier. When you exercise, your muscles actually hold onto water. If you're not adequately hydrated, you're preventing your muscles from operating at full capacity. You're much more likely to feel fatigued when you're thirsty, too, which may lead you to shorten or skip your workouts.

There are a few other non-weight-related benefits worth noting. If you're consuming more fiber-rich foods, like fruit, veggies and whole grains, drinking a lot of water can help prevent constipation. And studies show that drinking water can help ward off certain cancers, like bladder and kidney cancers. Drinking regularly helps dilute toxins and flushes them from your system, thus, reducing the amount of time they're in your body.
Keri Gans
Nutrition & Dietetics
You want to lose weight, right? Then water is your friend. It really does fill you up, and may help prevent you from filling out. In a study conducted at Virginia Polytechnic Institute and State University, researchers found that postmenopausal women who drank 1.5 cups of water before a meal reported that they felt fuller. As a result, they consumed about 60 fewer calories than those who didn’t drink water before a meal. If you think 60 calories isn’t much, try this strategy every day for a year. You’ll save a total of 21,900 calories, which is the equivalent of six pounds!
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Drinking water is certainly important for overall health and is a great choice for hydration because it is calorie and caffeine free. However, simply drinking water doesn't impact your hunger. Thirst and hunger are sensed by different mechanisms in your body. Thirst develops from a rise in electrolytes in your blood or a decrease in blood volume. Hunger signals stem from declines of available fuel (such as glucose) in your body. Because of these separate mechanisms, it is unlikely that your body confuses thirst with hunger. Studies comparing people who drink water immediately before, or during, meals with those that don't drink water show no difference in the amount of calories that they consume. Drinking water can help with weight loss if you find that, in the absence of hunger, you still eat just to have something in your mouth. Drinking water, instead of eating, in these instances can help you decrease your overall daily calorie intake.

Water is an essential nutrient your body needs to use to burn body fat! That’s why drinking water to lose weight is an important consideration in your weight loss program. We are made up of 55-75% water - that’s a lot of water! We need all of it for chemical reactions in physiological processes to burn fat and calories. It’s also used to transfer by-products of waste (from fat breakdown) away and out of our bodies. In some cases, when you’re dehydrated and there isn't enough water to dilute the body's waste products, kidney stones may form. The liver then has to step in to help the kidney. This taxes the liver, causing it to perform poorly for its other functions. This is really bad for weight loss because one of the major functions of the liver is to burn fat.

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Paula Greer
Midwifery Nursing

Drinking water will definitely help you in your weight loss endeavors. Many times when we think we are hungry because our body is sending out the message we need something, we get the signals crossed and miss the cue it is time to fill our tank with water. Confusing thirst and hunger may lead us into the path of temptations that a simple glass of water could fix. The next time you think you are hungry try drinking several glasses of water first. Studies show if you do you may eat around 200 calories less then if you hadn’t had the water first. When everyone is passing out the breadsticks I go for the water and a handful of nuts. By the time dinner arrives I am nowhere near as hungry as when I first set down to the table. Portion control is always easier when the ghrelin hormones aren’t screaming at you to eat everything in sight. I use a water bottle and try to make sure I drink at least 2 quarts a day.

Kirsi Bhasin
Nutrition & Dietetics

Water is essential to losing weight and being healthy, yet how much you need varies by individual. Chances are you are not getting enough.  

Sometimes when you think you are hungry you are in fact thirsty, it can be a signal from your body to drink. So next time you feel an extra pang of hunger in your day, drink water.

How much water should you drink each day? It's a simple question with no easy answers.  Studies have produced varying recommendations over the years, but in truth, your water needs depend on many factors, like how active you are and where you live.

Although no single formula fits everyone, knowing more about your body's need for fluids will help you estimate how much water to drink each day.

How much water do you need?

On average a healthy man needs about 13 cups while a healthy woman needs about 9 cups. So what about the 8 glasses a day? Think of it as eight 8-ounce glasses a day as a general rule of thumb.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.