Does Water Help You Lose Weight? What Research Shows

Water may indirectly aid weight loss, but it doesn't burn fat on its own or cause significant weight loss without changes in energy balance. The most compelling benefits appear in two situations: when water replaces sugary and other high-calorie drinks and when drinking before meals helps a person eat slightly less. Simply increasing water intake while maintaining an unchanged diet has not shown a consistent, independent effect on body weight. [1]

This is clearly demonstrated in a 2024 meta-analysis of eight randomized trials in people with overweight or obesity. On average, interventions that increased water intake resulted in a difference in body weight of only about -0.33 kg, with the confidence interval including both weight loss and small weight gain, meaning no statistically significant independent effect was found. The authors concluded that increasing water intake alone likely has little effect on fat mass, although replacing sweetened beverages with water may provide modest benefits. [2]

There are also a few small studies showing that drinking 500 ml of water before main meals did enhance weight loss. However, these studies were conducted primarily in middle-aged and older adults with excess weight, were relatively small, and do not support the claim that everyone who wants to lose weight should drink half a liter before every meal. [3]

Therefore, it's more reasonable to view water not as a weight-loss aid, but as a convenient tool: it doesn't contain energy, can replace a high-calorie beverage, sometimes enhances the feeling of fullness, and helps maintain normal hydration. However, current evidence doesn't support any specific volume of water that will trigger fat burning regardless of diet.

What modern research on water and weight loss shows

In 2024, two large summaries of randomized trials were published, and their findings clearly illustrate why there is conflicting advice around this topic.

The first systematic review, published in JAMA Network Open, analyzed 18 randomized trials of changing daily water intake across various conditions. Only four studies directly assessed body weight. In three of these, overweight or obese adults who were asked to drink extra water before meals lost more weight than control groups. However, the authors emphasized that the studies were few, the sample sizes were small, and the overall evidence base was limited. [4]

The second meta-analysis focused specifically on body weight and combined eight randomized trials. When all water interventions were combined, no statistically significant reduction in body weight was observed: the average difference was -0.33 kg. No significant reduction in body mass index or waist circumference was also found. [5]

At first glance, the findings appear contradictory, but in reality, they reflect different methods of analysis. The first review notes that some specific small trials have shown positive results, particularly with water before meals. The second asks a more rigorous question: what happens if you pool all randomized trials? The average effect becomes small and statistically inconclusive.

That's why the statement "research has proven that water helps with weight loss" is too strong. A more accurate statement would be that some water-based strategies may facilitate weight loss somewhat, but water is not a standalone treatment for obesity. [6]

How can water actually help?

There are several different mechanisms that are often mistakenly combined into one.

Possible mechanism	What the data shows
Replacing a sweet drink with water	The most logical and practically significant mechanism: energy supply decreases
Water before meals	In some studies, it reduced the amount of food eaten and slightly increased weight loss.
Reducing the feeling of hunger	It may be true for some people, but research results are inconsistent.
Acceleration of metabolism	No convincing significant effect was confirmed
Burning fat with water	Not proven
Cold water	Provides only a very small additional energy consumption for heating
Warm water	There is no specific fat burning benefit.
Water on an empty stomach in the morning	There is no evidence of any particular advantage to timing of consumption.
Lemon water	Does not have an established independent effect on fat mass

The difference between these mechanisms is fundamental. A person who replaces a liter of sugary soda with water every day actually significantly changes the energy value of their diet. However, someone who already drinks low-calorie beverages and simply adds two more liters of water to their diet may not change their energy intake at all.

The healthiest option is to replace high-calorie drinks with water.

If a person regularly drinks sugary drinks, replacing them with water is one of the most effective ways to use water for weight loss.

Sweetened beverages contain energy, but are generally less satiating than solid foods. The World Health Organization (WHO) notes that consumption of sugary beverages contributes to increased overall energy intake and is associated with unhealthy weight gain; the organization recommends limiting free sugars and sweetened beverages. [7]

In a 2024 systematic review of long-term randomized trials, replacing sugary drinks with non-caloric alternatives—water or sugar-free drinks—for 6–18 months was associated with an average reduction in body mass index of approximately 0.31 kg/m² compared with continuing to drink sugary drinks. For an adult, this corresponded to approximately one kilogram of difference in body weight during the intervention period. [8]

However, water doesn't "dissolve fat" in this situation. Something much simpler is happening: an energy source is being removed from the diet. If a bottle of sugary drink is replaced with water, the calories from it no longer need to be compensated for with additional energy expenditure.

This also explains why the effect will depend heavily on the initial diet. If a person doesn't drink sugary drinks at all, there's almost no chance of losing weight through such a substitution. However, if a person consumes several hundred kilocalories daily from soda, sweet tea, coffee with syrups, or energy drinks, there's much more room for change.

What if you just drink more water without changing anything else?

This approach is unreliable in itself.

In a 2024 meta-analysis, increasing water intake without necessarily changing other dietary components did not result in significant average weight loss. This means that the advice to "start drinking two liters and the weight will go away" lacks sufficient evidence. [9]

One randomized trial included in a larger 2024 review asked people who previously drank less than a liter of water per day to increase their intake to approximately two liters. No independent effect on body weight was found over six months. [10]

The reason is clear: water contains virtually no energy, but adding a zero-calorie food doesn't automatically detract from the diet. If a person drinks an extra glass of water and then eats exactly the same amount as before, their energy balance may remain unchanged.

So the main question when using water for weight control is not "how many extra liters did I drink?" but "what changed in my diet thanks to this water?"

Does drinking water before meals help you eat less?

For some people, yes, but the effect is not universal.

One of the most well-known experiments involved 48 adults aged 55-75 who were overweight or obese. Both groups followed a reduced-calorie diet, but one group drank an additional 500 ml of water before their three main meals. After 12 weeks, this group lost approximately two kilograms more. [11]

Another randomized trial in 84 obese adults compared 500 ml of water consumed approximately half an hour before main meals with a control group. After 12 weeks, the initial analysis showed approximately 1.3 kg greater weight loss in the water group. After statistical adjustment, the difference no longer reached the usual threshold for statistical significance, so the authors rightly called the result preliminary. [12]

The mechanism is likely related to gastric distension and subjective satiety. For example, in a small experiment in overweight and obese middle-aged and elderly adults, drinking 500 ml of water 30 minutes before breakfast reduced the amount of energy consumed at the subsequent meal. [13]

But age and circumstances may matter. In an earlier study, drinking water before meals reduced subsequent food intake in participants aged 60–80, but had no such effect in adults aged 21–35. [14]

Other small studies of young adults have found reduced food intake under certain conditions, so a simple "only works after age 60" line cannot be drawn. Rather, the evidence suggests that the effect of water on appetite varies greatly between individuals and depends on volume, timing of consumption, age, and experimental conditions. [15]

Is it worth drinking 500 ml before each meal?

For a healthy adult, this approach can be viewed as an optional behavioral experiment rather than a standard recommendation.

500 ml was used in many positive studies, usually taken approximately 30 minutes before meals. However, this dose was chosen for the experimental protocol and is not an established therapeutic dose for weight loss. [16]

If half a liter causes heaviness, nausea, belching, or simply an unpleasant feeling of fullness, there's no reason to endure it for the sake of a small potential effect. You can limit yourself to a smaller volume or abandon this method altogether.

Especially don't turn a small study's protocol into a rule of "500 ml 3 times a day plus regular fluids." Such an additional amount may be completely unnecessary for someone who is already well hydrated.

In practice, drinking water before a meal only makes sense if it really helps you calmly reduce your portion size without causing discomfort.

Should you drink water when you're hungry?

The popular advice "if you feel hungry, drink water first, because the body confuses hunger with thirst" sounds much more certain than scientific evidence suggests.

Thirst and hunger are regulated by different systems, although subjective sensations may overlap. Studies of increased drinking show that the sensation of fullness after drinking water is indeed possible, but increased water intake does not always reliably reduce subsequent food intake. In experimental studies, subjective hunger and actual food intake often changed differently. [17]

Therefore, a person doesn't need to suppress true hunger with water every time. If it's time to eat and normal physiological hunger is present, water doesn't replace a full meal.

A different matter is a regular snack paired with a sweet drink or a situation where a person is genuinely thirsty. A glass of water can help you understand your own feelings, but it shouldn't be used as a universal appetite suppressant.

Does water speed up metabolism?

Modern research does not confirm a significant “boost in metabolism” sufficient for weight loss.

The widespread claim emerged from a small 2003 study. In 14 participants, after drinking 500 ml of water, the researchers recorded approximately a 30 percent short-term increase in energy expenditure and calculated that two liters of water could theoretically significantly increase daily energy expenditure.[18]

However, later experiments failed to replicate this large effect. In a randomized study, drinking approximately 500 ml of room-temperature water did not significantly increase energy expenditure. Very cold water, around 3°C, produced only a small increase in energy expenditure—approximately 4.5% over an hour. [19]

In another 2015 controlled study of 27 adults, the increase in energy expenditure after drinking 500 ml of water was less than 3% and was not significantly different from a control period without drinking. No significant increase in fat oxidation was also found. [20]

Therefore, you shouldn't expect that drinking a few glasses of water every day will burn a significant amount of additional calories.

Is it true that cold water helps you lose weight better?

The body does physically have to heat cold water to body temperature, and this requires some energy. But the scale is too small to use cold water as a weight loss tool.

In a study where water was cooled to approximately 3°C, energy expenditure increased by approximately 4.5% over one hour. Room temperature water had no noticeable effect.[21]

Even if such a small change does occur, it's not comparable to the energy value of a typical snack or sugary drink. Therefore, deliberately drinking ice water for fat loss is pointless.

It's best to choose the temperature based on your comfort level. If cool water feels better, you can drink cool. If warm, you can drink warm. The difference in temperature makes virtually no difference in terms of changes in fat mass.

And warm water in the morning?

There is no proven weight loss effect from drinking warm water in the morning.

Studies that have found water's potential benefits for weight management have examined beverage replacements or water before meals, rather than the mandatory glass of warm water upon waking. Systematic reviews have not identified a specific morning mechanism that would cause the body to more actively use fat stores. [22]

Drinking water in the morning is fine if it helps maintain normal hydration. However, there's no need to wait for "metabolism to kick in" or drink a specific amount on an empty stomach.

Moreover, if we consider the purely thermodynamic costs of changing the temperature of a liquid, cold water requires little energy to heat, while warm water does not. Even this effect is too small to have practical significance for weight. [23]

Does lemon water help you lose weight?

Lemon does not turn water into a fat-burning drink.

If a few lemon wedges make water more palatable, making it easier for a person to replace sweet juice, lemonade, or soda with plain water, this habit may indirectly aid weight control. However, this is a drink substitution effect, not the effect of lemon on fat cells.

Systematic reviews of randomized water trials do not show that lemon addition is necessary for effects on body weight.[24]

The situation changes if honey, sugar, or syrup is added to "lemon water." This drink already contains energy, so it can't be considered equivalent to plain water.

Do you need to drink two liters of water to lose weight?

There is no specific “two liters for weight loss” standard.

The European Food Safety Authority uses a guideline for total water intake of approximately 2.0 liters per day for women and 2.5 liters for men. However, this refers specifically to total water intake—from beverages and food—and not the amount of pure water that should be consumed additionally. These values are hydration guidelines, not weight-loss doses. [25]

The British health system uses a simpler guideline—approximately 6-8 cups or glasses of fluid per day for most people—emphasizing that this is only a guideline. Needs increase during heat, prolonged physical activity, pregnancy, breastfeeding, and certain illnesses. The total volume also includes tea, coffee, milk, and other water. [26]

Therefore, formulas like "30-40 ml per kilogram of body weight is essential for weight loss" cannot be considered a universal international standard. For a person weighing 120 kg, such a mechanical formula could provide a very large volume of fluid without a proven need.

The need for water is determined not by the amount of excess fat a person wants to lose, but by the body's water balance, climate, nutrition, physical activity, age and health status. [27]

Should I drink more than the recommended amount while losing weight?

If you are already sufficiently hydrated, there is usually no need to specifically increase your water intake to speed up weight loss.

Reducing calorie intake can sometimes actually reduce the amount of water previously absorbed from food and beverages. Physical activity can also increase fluid loss through sweat. In such situations, fluid intake should be adjusted according to loss and thirst.

But the principle that "the more water you drink, the faster you lose fat" is unproven. In a meta-analysis of randomized trials, simply increasing water intake did not result in a significant average reduction in body weight. [28]

A good everyday guideline is the absence of noticeable thirst and typically light yellow urine throughout the day, although urine color can vary due to medications, vitamins, and other factors. British guidelines recommend this practical approach rather than mandatory milliliter counting. [29]

Can water reduce appetite for a long time?

The effect is mostly short-term and not permanent.

Water increases the volume of stomach contents, so some feeling of fullness is quite possible. This mechanism is likely at play in studies of drinking water before meals. However, liquid quickly empties from the stomach, and water itself does not contain protein, fiber, fat, or other food components that contribute to longer-lasting satiety.

Experimental data also show that a reduction in subjective hunger does not always translate into a reduction in actual food intake. In a study of increased water intake, hunger and food preferences changed, but energy intake was not reliably suppressed. [30]

Therefore, water can be a complementary tool, but it does not replace a diet with sufficient protein, dietary fiber, and adequate total energy value.

Water cannot replace energy deficiency

This is the main physiological limit of any “water diet”.

To reduce fat stores, the body must expend more energy than it takes in over time. The American Heart Association's updated 2026 guidelines continue to emphasize matching energy intake to energy expenditure as one of the key principles for maintaining healthy body weight. [31]

The World Health Organization also considers energy intake, diet quality, physical activity, sleep, and other behavioral factors as elements of the prevention and treatment of excess body weight. Simply increasing water intake is not a stand-alone method for treating obesity. [32]

Therefore, two opposing situations are possible. One person drinks enough water but continues to experience an energy surplus and gains weight. Another person drinks exactly the same amount of water but reduces the overall energy value of their diet and loses weight. It's not the water itself that makes the difference.

Why might the scale show more weight after drinking water?

After drinking large amounts of liquid, your body weight may temporarily increase on the scale. This does not indicate an increase in fat mass.

One liter of water weighs approximately one kilogram, so immediately after drinking a liter, the scale may physically show more. Subsequently, the water is distributed among the body's fluid compartments, and its excess is eliminated by the kidneys. In a healthy person, the kidneys and thirst mechanisms constantly regulate water balance. [33]

For this reason, daily weight changes of several hundred grams or even more may reflect water, the amount of food in the gut, salt, and other short-term factors, rather than changes in fat stores.

When losing weight, it's more helpful to evaluate weight trends over several weeks under similar measurement conditions rather than interpreting every morning change as fat loss or gain.

"Water loss" and "fat loss" are different processes.

During the first days of carbohydrate restriction or overall calorie reduction, body weight can sometimes decrease quite rapidly. Much of this early weight loss may be due to water retention rather than the loss of a few pounds of fat.

The opposite is also true: after eating more salt, changing the amount of carbohydrates, or drinking a large volume of liquid, weight may temporarily increase, although the person continues to be in an energy deficit.

Therefore, drinking less water specifically to achieve a lower number on the scale is a poor strategy. It creates a temporary loss of fluid mass, not a reduction in fat stores.

Normal hydration should be maintained regardless of what the scale shows today.

Is it possible to lose weight by replacing juice with water?

It depends on the type and amount of juice, but such a substitution can indeed reduce the energy value of the diet.

The World Health Organization classifies fruit juice sugars as free sugars and recommends limiting their overall intake. Unlike whole fruit, juice is easier to consume in significant quantities and provides additional energy. [34]

If a glass of juice is replaced with water without subsequent calorie compensation through food, daily energy intake decreases. This is the same mechanism that occurs when replacing sugary soda.

This doesn't mean that one glass of juice will necessarily hinder weight loss. The entire diet is important. But from a beverage perspective, water is a simpler, energy-free option.

Sugar-free drinks or water - which is better for weight loss?

The data here is more interesting than the popular dichotomy of “water is good for you, everything else hinders weight loss.”

Randomized trials do not consistently show the superiority of water over all non-caloric beverages for weight loss. In one systematic review of 17 randomized trials, low-calorie sweetened beverages produced modest weight loss when replacing sugary drinks, but when compared directly with water, the results did not show a consistent advantage for water. [35]

A meta-analysis of studies lasting at least six months also found that replacing sugary drinks with non-caloric options—both water and sugar-free drinks—was associated with small improvements in body weight during the intervention period.[36]

This doesn't mean everyone should switch to sweetened drinks. Water remains a simple, sugar-free, energy-free beverage. But from a weight-management perspective, the key is often the removal of the calorie-laden beverage, not any special fat-burning properties of water.

Can you replace food with water or water with food?

Water is not a substitute for a full meal.

Trying to regularly skip meals and suppress hunger with large amounts of water may temporarily reduce energy intake, but this is a form of severe dietary restriction, not a proven benefit of water.

When losing weight, your diet should still provide essential nutrients. Modern recommendations focus on a sustainable diet with whole foods, rather than displacing food with water. [37]

If water is used before a meal to slightly increase satiety, and then the person calmly consumes a full meal, this is a completely different approach.

Can drinking too much water be harmful to your health?

Yes. More water is not always better.

The body can regulate a significant range of fluid intake, but if more water is taken in than the kidneys can excrete under given conditions, the sodium concentration in the blood may decrease. This condition is called hyponatremia. Severe, rapid sodium depletion can cause headache, confusion, seizures, and, in the most severe cases, coma. [38]

Most healthy people do not experience this complication simply by drinking. The risk increases with intentional consumption of very large volumes, certain medical conditions, certain medications, or impaired kidney function. [39]

Therefore, the idea that “to lose weight faster, you need to drink four to five liters regardless of thirst” has no proven benefit and can potentially cause harm.

Who shouldn't just increase the amount of water?

For some conditions, the advice to "drink more" may be incorrect.

The National Kidney Foundation notes that in advanced chronic kidney disease, and especially kidney failure, a person may need to restrict fluid intake because the kidneys excrete insufficient fluid. Excess fluid can contribute to swelling, shortness of breath, and high blood pressure. [40]

Some people with heart failure, liver disease, severe sodium imbalances, or taking certain medications also receive individualized fluid intake recommendations. In these conditions, advice to drink extra liters of water for weight loss should not replace a medical regimen. [41]

The same applies to people with constant, unusual thirst and excessive urine output. Here, it's important to first understand the cause of the water imbalance, rather than using even more water as a weight control method.

Practical: When Water Can Really Help You Lose Weight

The most sensible approach is not to mandate a certain number of liters, but to use water where it actually changes behavior or energy balance.

Situation	A practical approach	How justified is it?
Every day I drink sweet soda	Replace with water	A well-founded way to reduce free sugars and energy intake
Sweet coffee or tea is often drunk	Replace some drinks with water or reduce sugar	May reduce calorie content
It's difficult to control portion sizes before eating.	You can test your water tolerance before eating.	Possible small benefit, evidence limited
Enough non-caloric liquid is already being drunk	There is no need to add a few more liters on purpose.	No additional effect on weight has been proven.
I want to speed up my metabolism	Increasing water for this purpose makes no sense.	A pronounced thermogenic effect has not been confirmed.
Lemon water is used for fat burning.	You can drink it for the taste, but don't expect any special effects.	Fat burning effect has not been proven
Have kidney disease or fluid restriction	Do not increase the volume on your own	An individual regime is required

What can you try without a complicated scheme?

If your primary goal is weight loss, it's helpful to first evaluate your beverage intake over a typical day. This is often where easily eliminated calories are found: soda, juice, sweet tea, coffee with sugar, syrup, or cream, energy drinks, and sports drinks.

The World Health Organization recommends limiting free sugars to less than 10% of total dietary energy intake and considers reducing sugary drinks as one of the measures to prevent unhealthy weight gain. [42]

If high-calorie drinks are scarce, drinking more water is unlikely to be the primary weight-loss lever. Portion size, energy density of foods, nutritional quality, physical activity, and the ability to maintain a consistent routine are then much more important. [43]

Water before meals can be tested as an optional measure. If drinking a glass of water some time before a meal makes a smaller portion more comfortable, it's potentially beneficial. If nothing changes or you experience uncomfortable fullness, you can safely abandon the method.

What is often misunderstood

"Two liters of water a day burns extra calories." Older small studies did report a significant increase in energy expenditure, but more recent controlled experiments have failed to replicate this effect.[44]

"Cold water forces the body to burn a lot of calories to warm itself up." There is an additional burn, but in the experiment it was very small—approximately 4.5% increase in energy expenditure only for an hour after drinking very cold water. This effect has almost no practical significance for weight loss. [45]

"The more water you drink, the faster you lose weight." In a meta-analysis of randomized trials, increasing water intake alone did not significantly reduce body weight.[46]

"If you're hungry, you're actually thirsty." Water sometimes temporarily increases feelings of fullness, but experimental data do not show reliable suppression of food intake in all people. [47]

"Lemon water burns fat better than regular water." Systematic studies of water and weight do not support a separate fat-burning effect for lemon water. The benefits appear primarily when this sugar-free drink replaces a high-calorie drink. [48]

"To lose weight, you absolutely need to drink two to three liters of pure water." Hydration guidelines apply to total water intake, including beverages and food, and are not intended as a dosage for weight loss.[49]

Frequently Asked Questions

How much water should you drink per day to lose weight?

There is no specific amount for weight loss. You should drink enough to maintain normal hydration. The European reference intake for total water is approximately 2.0 liters for women and 2.5 liters for men, including water from food and all beverages. Individual needs vary depending on temperature, activity, and health status. [50]

Is it true that you need to drink two liters of clean water?

No. Population recommendations include water from food and other beverages. Tea, coffee, and milk also contribute to fluid intake. [51]

Is it possible to lose weight if you just start drinking more?

Sometimes weight gain changes slightly, especially if water replaces caloric drinks or helps you eat less. But on average, randomized trials don't show significant weight loss from increasing water intake alone. [52]

How much water should you drink before eating?

In studies, the most common dose used was about 500 ml, taken approximately 30 minutes before meals. This is an experimental protocol, not a universal medical standard. If this volume is unpleasant, there is no need to adhere to it. [53]

Does drinking a glass of water before breakfast help you lose weight?

There is no proven benefit specifically from breakfast. Drinking water before meals has been shown to slightly reduce food intake in some studies, but the effect was inconsistent. [54]

Should you drink water on an empty stomach in the morning?

For weight loss, no. If you're thirsty in the morning, water is a good drink, but there's no specific "fat-burning window" after waking up. [55]

What is better for weight loss - cold or warm water?

No significant difference has been proven for fat loss. Very cold water causes a small energy expenditure for heating, but this amount is too small for practical weight loss. [56]

Does lemon water help with belly fat?

There's no evidence for a specific effect on belly fat. If unsweetened lemon water replaces calorie-rich drinks, it may help reduce energy intake.

Is it okay to drink water during meals when losing weight?

Yes. If water is well tolerated, there's no need to prohibit it. For weight control, what matters is whether the chosen regimen helps manage overall calorie intake, not the fact of drinking during meals.

Can water reduce evening appetite?

Sometimes the feeling of fullness after drinking water reduces subjective hunger, but the effect is not guaranteed. If a person is truly hungry, constantly replacing food with water should not be done. [57]

If I drink three liters, will I lose weight faster than if I drink two?

This relationship has not been proven. With sufficient hydration, an extra liter does not become an additional fat burner. [58]

Can too much water be dangerous?

Yes. When water intake is excessive relative to the body's ability to eliminate it, blood sodium levels can decrease. Severe hyponatremia can cause neurological symptoms, including confusion and seizures. [59]

Should you drink more after a workout to lose weight?

It's important to replenish fluid lost through sweat, especially in hot weather and during prolonged exercise. However, drinking more than necessary does not enhance fat loss. [60]

What is more effective: water or cutting out 200 kilocalories of food?

If the comparison truly means maintaining an energy deficit, a direct reduction in energy intake has a more understandable mechanism for weight loss. Water can help create such a deficit, for example by replacing a calorie-rich beverage, but it does not replace it. [61]

Key points from experts

Brenda Davey, PhD, RD, is a professor in the Department of Human Nutrition, Food, and Physical Activity at Virginia Tech. Her research interests include obesity, weight regulation, eating behavior, beverages, and weight management; her university profile lists water and body weight research as one of her primary areas of research. [62]

Davey's research group conducted several controlled experiments with drinking water before meals. In studies of middle-aged and older adults, this approach reduced food intake and, when combined with a reduced-calorie diet, was associated with somewhat greater weight loss. A later review by the group in 2025 characterized these results as evidence of the fundamental potential of using water before meals to manage appetite, rather than as a universal, standalone treatment for obesity. [63]

Benjamin Breyer is a physician, professor and chair of the Department of Urology at the University of California, San Francisco, professor of epidemiology and biostatistics, and a master of clinical research. His academic appointments are confirmed by the university's official profile. [64]

Breyer led a team that conducted a systematic review of randomized trials of water intake modifications, published in 2024. In the university's official explanation, he notes that water is a simple and common intervention, but the high-quality evidence base for its therapeutic effects was surprisingly small. In terms of weight, several trials showed benefits, but the systematic review itself emphasizes the limited number of studies. [65]

Main

Water can aid weight loss, but mostly indirectly. The most obvious mechanism is its role as a substitute for sugary and other calorie-rich drinks. This reduces energy intake without requiring a reduction in food intake. Drinking water before meals may also be beneficial for some people, but the studies are small and the results are far from universal. [66]

However, ideas about a significant acceleration of metabolism, fat burning with cold water, the special benefits of warm water on an empty stomach, or the mandatory two to three liters for weight loss are not convincingly supported. Later controlled studies have not replicated the significant "thermogenic" effect of water described in earlier studies. [67]

In practice, water works best as a substitute for high-calorie drinks and sometimes as an aid to portion control, rather than as a standalone weight loss aid. You should drink enough to stay hydrated, but there's no need to force yourself to drink a few extra liters for weight loss. For kidney disease and other conditions requiring fluid restriction, fluid intake should be determined individually. [68]