How does drinking water affect your weight?

You need enough water every day to restore fluids you lose in daily life through your breath, sweat, digestion, and elimination. You'll often read that you should drink water to lose weight, but there isn't much evidence that this is true.
You need enough water every day to restore fluids you lose in daily life through your breath, sweat, digestion, and elimination. You'll often read that you should drink water to lose weight, but there isn't much evidence that this is true.

Water is essential for your health. You need enough water every day to restore fluids you lose in daily life through your breath, sweat, digestion, and elimination. Water hydrates your skin, keeps your joints lubricated and healthy, and keeps your body cool. 

You'll often read that you should drink water to lose weight, but there isn't much evidence that this is true. Water makes up 60 percent of your weight: obviously, weight and water are related. That doesn't mean drinking water will help you lose weight, though. 

Your body tightly controls your water levels to protect against dehydration and overhydration. Both of these conditions can lead to slight changes in your weight. But your body works hard to keep your water levels in balance, so water-weight tends to be temporary. Water-weight also is not the same thing as weight caused by fat stores or, for that matter, the weight of muscle or any other material in your body.

Dehydration

In some cases, If you lose a lot of fluids, your body will compensate by holding onto the fluids you do have. This can cause bloating or water retention, which can make you look heavier. Water retention can be a side effect of dehydration and fluid loss from using laxatives for weight loss.

Overhydration

Your kidneys help get rid of extra water in the form of urine. If you have too much fluid in your body, you'll urinate a lot. If you take in more water than your kidneys can handle, you can have swollen legs and bloating. This is also true if your body fails to process normal levels of water as a result of an underlying condition.

Salt intake

High salt intake can also cause your body to hold onto water. Your body will automatically try to dilute salt by slowing down urinating and holding on to water. You will feel thirsty and want to drink water as your body tries to regain its balance. If that doesn't work, your body will strip water from your cells and pour it into your blood. Extra salt can make you puffy and bloated, making you appear heavier. 

Behavior changes

But drinking water doesn't make you lose fat-related weight. Instead, the connection between drinking water and weight loss is behavior change. 

You might mistake your thirst for hunger. If you drink water instead of eating a snack, this can help you stop overeating, which will help with weight loss. A glass of water might also make you feel full, so you'll eat less, which again leads to weight loss. 

Water is calorie-free. Sodas and other sweet, sugary drinks are key sources of calories you might not consider. By simply swapping your drinks for water, you can lower your calories, which will help with weight loss.

Since water lubricates your joints, drinking plenty of water might help with soreness and stiffness. If your joints feel better, you might exercise more, another way to support weight loss. 

These changes in behavior can affect your weight, but it's not necessarily the water itself that causes weight loss. 

Does drinking water reduce belly fat?

On the other hand, it's possible that drinking water might help lower your belly fat. Some studies show that drinking water can increase your resting energy expenditure. This is the rate at which you burn calories when you're resting. The study shows the shift happened within 10 minutes of drinking a glass of water and lasted for 1 hour. 

Other studies show that drinking water increases lipolysis. This is the process in which water breaks fat down into individual molecules in your body. Studies show that drinking water can burn fat and increase metabolism in general. 

A lot of these studies are done on animals. It's not clear that this is true for people. More studies are needed.

How should you lose weight?

Drinking water is important for your health and can help in managing your weight. Switching to water instead of sugary drinks reduces the sugar and calories in your diet. But water isn't a magic trick for weight loss. The idea that drinking lots of water helps you lose weight fast is a diet culture myth. 

The best way to lose weight is to burn more calories than you eat and drink. You can do this by lowering your calories and increasing your exercise

Lower your sweets, treats, and fast foods and eat a healthy diet rich in fruits, vegetables, nuts, seeds, whole grains, healthy fats, and lean meats. Get at least 150 minutes of intense exercise every week. 

If you need help with your diet, talk to your doctor. A personal trainer can help you develop an exercise plan, but you can exercise for free, too. Try cycling, walking, swimming, or jogging.  

Some medical conditions like thyroid disease can cause weight gain and trouble losing weight. If you're having trouble losing weight, talk to your doctor.

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Medically Reviewed on 12/8/2021
References
SOURCES:

Brown University Health Services: "Laxative Abuse."

Frontiers in Nutrition: "Increased Hydration Can Be Associated with Weight Loss."

Harvard Medical School Harvard Health Publishing: "Diet & Weight Loss."

Harvard T.H. Chan School of Public Health: "Salt and Sodium." "Water."

Journal of Natural Science, Biology, and Medicine: "Effect of excessive water intake on body weight, body mass index, body fat, and appetite of overweight female participants."

Merck Manual Consumer Version: "Quick Facts Overhydration."

National Health Services: "10 weight loss myths," "Obesity," "Water, drinks, and your health."

National Institute of Health National Heart, Lung, and Blood Institute: "How Much Physical Activity Should Your Family Get?"

Texas A&M University Health Vital Record: "You Asked: What Is Water Weight?"