Does Drinking Water Help You Lose Weight?

Does drinking water help you lose weight? Believe it or not, it can. While this might sound too good to be true, there’s some solid science behind it.

Studies show that drinking water can reduce your appetite, stimulate your metabolism, and increase fat burning. And if you’re swapping sugary sodas for water, you’ll be reducing your overall calorie intake, too, which can help with weight loss.

But it’s not quite as simple as downing a glass of water or two. 

Read on to learn how drinking water can help you lose weight and how much water you should be aiming for.

It’s true: Drinking water can help you lose weight. 

A 2014 study had 50 female participants with excess weight drink roughly 51 ounces on top of their usual daily water intake. This was divided into about 17 ounces a half-hour before breakfast, lunch, and dinner. Participants drank the extra water for eight weeks.

At the end of the experiment, participants had a decrease in: 

• Body weight

• Body mass index (BMI)

• Body fat

• Appetite

More recent research has had similar findings. A 2022 review of studies concluded that “preloading water” — drinking water before meals — can promote weight loss. 

More specifically, drinking about 17 ounces before sitting down to eat may improve weight loss by two to five pounds over three months.

Not bad for the humble glass of water. Let’s dive into the specifics about how drinking water can help you lose weight. 

1. Water Suppresses Your Appetite 

Our brains are clever, complex things, but they often mix up the signals for thirst and hunger. When you drink more water, you’re less likely to feel “hunger” that’s actually just dehydration.

Water may also impact hunger hormones, including:

• Ghrelin: This is the hormone that signals hunger to the brain.

• Leptin: Leptin is an appetite-suppressing hormone.

• Insulin: When insulin is imbalanced, you might feel hungry.

• Cholecystokinin: This hormone stimulates the digestion of protein and fat. 

• Glucagon-like peptide-1: Also called GLP-1, this hormone contributes to feeling full. 

In simple terms, drinking more water can suppress your appetite while helping you feel fuller and more satisfied at meal times. This can lead to eating less, promoting weight loss.

For example, a 2021 study on people with type 2 diabetes found that drinking about 34 ounces of water a day before meals led to consuming fewer calories and fat.

Over eight weeks, and compared to the control group who didn’t drink any water before meals, this resulted in:

• A lower BMI

• A smaller waist circumference

• Greater weight loss 

Drinking water also seemed to reduce levels of copeptin, a protein that — in high levels — is linked to a larger waist circumference, elevated blood pressure, high BMI, and obesity.

2. Water Stimulates Your Metabolism and Burns Calories

Does water increase metabolism? Again, it sounds like wishful thinking, but the science is there. 

Water may increase thermogenesis (heat production) in the body. This, in turn, increases your metabolic rate, providing you with more energy to move and burn off excess weight.

A 2003 study on 14 participants found drinking about 17 ounces of water increased metabolic rate by 30 percent. The effect started kicking in 10 minutes after drinking water and reached its peak in 30 to 40 minutes.

In absolute terms, the number of calories burned by doing this wasn’t extreme, but on a weight loss journey, every bit can matter. 

Drinking colder water, it seems, burns more calories, because of the energy your body uses heating the water up.

3. Water Can Increase Fat Oxidation 

Water may increase the rate of lipolysis — the breakdown of fat for energy in your body. 

It becomes easier for your body to break down the fat in free fatty acids and transport it into mitochondria, which turn nutrients into energy in your cells. This means drinking water may increase fat oxidation, when your body burns fat for fuel.

4. Water Reduces Your Overall Liquid Calorie Intake 

Ever wondered, does water have calories? The answer to that is, simply, no.

So, swapping soft drinks, sugar-laden fruit juices, or alcoholic beverages for water can help you reduce how many calories you consume.

Swapping your usual lunchtime cola and after-dinner beer for a glass of water is a simple change that cuts calories before you even think about overhauling your diet. 

Plus, if you stay hydrated with zero-calorie water, you’re less likely to reach for a sugary, high-calorie drink to quench your thirst.

5. Water Makes Exercising Easier 

If you’re on a weight loss journey, you might be trying to add some more physical activity to your day. Good for you. Drinking water can help make this lifestyle change easier. 

When exercising, even mild dehydration can lead to: 

• Reduced endurance 

• Reduced motivation 

• Increased fatigue

• Increased perceived effort — your workouts feel harder 

Drinking enough water can reverse these effects and reduce the oxidative stress that exercise can cause.

When working up a sweat, you’ll lose more water than usual. So it’s even more important to keep a water bottle nearby and make sure you’re sippin’ on it throughout your workout.

You may have heard you should aim for eight cups of water a day for optimal health. But there’s actually no hard-and-fast rule about how much water you should drink — and that’s even more true when it comes to drinking water for weight loss.  

The National Academies of Sciences, Engineering, and Medicine recommends about: 

• 91 ounces of water a day for women

• 125 ounces of water a day for men 

However, this is total fluid intake from food and drinks — not just glasses of water alone. 

Also, the numbers are not the same for everyone. How much water you need depends on factors like your daily activity levels and how hot it is where you live.

And that’s just when thinking about water for general health and well-being. How much water you should drink to lose weight might be whatever’s necessary to suppress appetite and reduce calorie intake — or it could all be about timing (i.e., upping your water intake before meals). More research is needed on that front. 

For now, we say don’t worry too much about how much water a day for weight loss is best. Our advice is to drink when you feel thirsty, check that your pee is clear or light yellow (dark yellow signals dehydration), and consider drinking a little extra before meals to see if it affects your hunger and meal satisfaction.

Now that we’ve established that drinking more water could help you lose weight, it’s time to drink up.

Here are some tips to increase your water intake: 

• Carry a water bottle with you everywhere — bonus points if it’s a reusable bottle you enjoy using.

• Add a slice of lemon, lime, or cucumber to your water if you need to jazz up the taste of plain water — or drink sparkling water.

• Drink water with meals — make it a non-negotiable on your dinner table. 

• Freeze bottles of water or add ice cubes to your glass to enjoy cold water. 

• Have a glass or bottle of water on your desk, next to the couch, in your gym bag, etc. Sometimes, you just need the visual cue to drink up.

• Set reminders on your phone, download a water-drinking app (yep, those exist), or leave a Post-It note on your bathroom mirror. 

We’ve answered the burning question of “does water help you lose weight?” But weight loss isn’t the only benefit of drinking more water. 

Beyond helping you reach your weight loss goals, water can help boost: 

• Mental performance and energy. When dehydrated, you may find it harder to concentrate and stay alert. Your short-term memory could take a hit, too.

• Physical performance. Dehydration can lead to reduced endurance and increased fatigue and perceived effort — not what you want when working out.

• Overall health and wellness. Adequate hydration can reduce your chances of kidney stones, constipation, exercise asthma, urinary tract infections (UTIs), high blood pressure, and possibly fatal coronary heart disease. It might also lower your risk of developing a headache. Water can even help your hair grow.

Can Water Fasting Help You Lose Weight? 

Water fasting — when you don’t eat any food and only consume water for a set period of time — can help you lose weight. However, it’s not generally recommended by healthcare professionals, as it can be dangerous to your health.

If it’s something you’re considering, speak to a healthcare provider first and fast under medical supervision. 

Keep in mind that your provider may recommend healthier — and, let’s be honest, more enjoyable — ways of losing weight. This could include eating more whole foods and incorporating more movement into your schedule.

When Should You Drink Water for Weight Loss? 

There’s no best time to drink water for weight loss. That said, research suggests that drinking water before meals could help you eat fewer calories.

Try drinking 17 ounces — about a pint glass — of water 30 minutes before meals.

Outside of meal times, drink plenty of water throughout the day. And avoid waiting until just before bed to get in your daily water intake — otherwise, you’ll be setting yourself up for many middle-of-the-night bathroom trips.

The rumors are true: Drinking water can help you lose weight.

Here’s what you need to know about good ol’ H2O:  

• Drinking water has multiple benefits. It can reduce hunger, boost metabolism, and increase fat oxidation while helping you stick to a workout plan. You might find you’re eating (and drinking) fewer calories when you start upping your water intake.

• Drinking water before meals could help you eat fewer calories. A rigid water-consumption schedule may not be necessary. Still, you might try a glass or two about 30 minutes before meals. It could suppress your appetite, help you avoid overeating, and make you feel more satisfied.

• Don’t forget other essential factors for weight loss. Water is just one piece of the weight loss puzzle. If you’re drinking water to lose weight, don’t neglect nutritious foods (including protein), exercise, stress management, and sleep. 

Don’t be afraid to reach out to a healthcare provider for support and guidance. They can recommend the best weight loss treatments for you. Drinking water may be part of the strategy, but it may also include a meal plan, exercise routine, behavioral change tools, or weight loss medication.