Researchers are still unsure why drinking more water helps a person to lose weight, but many studies show some positive correlation between increased water consumption and weight loss.
Below are six reasons that water may help with losing weight.
1. Water is a natural appetite suppressant
When the stomach senses that it is full, it sends signals to the brain to stop eating. Water can help to take up space in the stomach, leading to a feeling of fullness and reducing hunger.
A person may also think that they are hungry when they are actually thirsty. Drinking a glass of water before reaching for something to eat can help to curb unnecessary snacking.
In a 2014 studyTrusted Source, 50 overweight females drank 500 milliliters (mL) of water 30 minutes before breakfast, lunch, and dinner, in addition to their regular water consumption, for 8 consecutive weeks.
The participants experienced a reduction in body weight, body fat, and body mass index. They also reported appetite suppression.
A studyTrusted Source from the previous year had yielded similar results.
2. Water increases calorie burning
Some research indicates that drinking water can help to burn calories.
In a 2014 studyTrusted Source, 12 people who drank 500 mL of cold and room temperature water experienced an increase in energy expenditure.
They burned between 2 and 3 percent more calories than usual in the 90 minutes after drinking the water.
Water may also temporarily increase the body’s resting energy expenditure, or the number of calories burned while resting.
Drinking cold water may further enhance water’s calorie-burning benefits, because the body expends energy, or calories, by heating up the water for digestion.
3. Water helps to remove waste from the body
When the body is dehydrated, it cannot correctly remove waste as urine or feces.
Water helps the kidneys to filter toxins and waste while the organ retains essential nutrients and electrolytes. When the body is dehydrated, the kidneys retain fluid.
When waste builds up in the body, people may feel bloated, swollen, and tired. Bloating can add inches to a person’s waist.
Staying hydrated is a good way to avoid retaining waste, which may add a few extra pounds.
For more science-backed resources on nutrition, visit our dedicated hub.
4. Drinking water can reduce overall liquid calorie intake
It is easy to accumulate liquid calories by drinking soda, juice, or sweetened coffee or tea.
Most people also ignore how many calories they consume in sports drinks or alcoholic beverages.
Replacing even a few high-calorie drinks each day for water or other no-calorie beverages, such as herbal tea, may have long-term weight loss benefits.
Authors of a 2012 studyTrusted Source found that replacing two or more high-caloric beverages for non-caloric drinks every day for 6 months resulted in an average weight loss of between 2 and 2.5 percent in a group of females with obesity.
In a studyTrusted Source from 2015, female participants drank 250 mL of water after lunch each day while attending a 24-week weight loss program. They lost 13.6 percent more weight than women in the same program who drank the same volume of diet beverages after lunch.
Results of a large-scale studyTrusted Source showed that men and women who replaced one serving of a sugar-sweetened beverage for water or a low-calorie drink every day for 4 years gained 0.49 fewer kilograms (kg) than a similar group who had made no changes.
The same study found that adults who replaced at least one serving of fruit juice with water or a low-calorie drink gained 0.35 kg less than their counterparts.
5. Water is necessary to burn fat
Without water, the body cannot properly metabolize stored fat or carbohydrates.
The process of metabolizing fat is called lipolysis. The first step of this process is hydrolysis, which occurs when water molecules interact with triglycerides (fats) to create glycerol and fatty acids.
Drinking enough water is essential for burning off fat from food and drink, as well as stored fat.
A mini-reviewTrusted Source from 2016 found that increased water intake led to increased lipolysis and a loss of fat in animal studies.
6. Water helps with workouts
One of the most important components of any weight loss plan is exercise.
Water helps muscles, connective tissues, and joints to move correctly. It also helps the lungs, heart, and other organs to work effectively as they ramp up activity during exercise.
Being hydrated reduces the risk of things that can get in the way of a good workout, such as muscle cramps and fatigue.
Always drink water before, during, and after exercise to avoid dehydration.
Keeping water close at hand is essential, especially if exercising in hot, humid, or very sunny conditions.