Drinking water to lose weight is a practice that many people indulge in. I also do that as well, especially on occasions when I am trying to stretch the limits of my intermittent fasting sessions.
But because people do things and recommend them is not enough for us to continue the tradition without making inquiries. And that is why I am making this post. To seek out the scientific facts support water drinking for weight loss, if any.
And this is me keeping true to my promise of always providing the best weight loss tips out there by doing the research and when possible, debunk claims that don’t make sense through the aid of studies proving the falsehood.
As we already know, water is very important for our overall wellbeing. It is said that about 60% of our body weight is made of water. And it is needed for every single body function. It helps to flush toxins from our organs, carries nutrients to our cells, supports our joints, and helps digest the food we eat.
There are numerous studies out there that prove, that more water drinking may be able to aid in weight loss and maintenance.
In a research involving 4963 retrieved records, 11 original studies and 2 systematic reviews it was discovered that increased water consumption, in addition to a program for weight loss or maintenance, reduced body weight after 3-12 month compared with such a program alone. 
But how does it work? How does drinking water to lose weight outside of mere statistics. Together we can find out that answer below.
In one study it was discovered that drinking 500 ml water prior to each main meal of hypocaloric diet (hypocaloric diet is one in which there is a reduction of daily calories or foods with high caloric density usually in order to aid weight loss.) leads to greater weight loss than a hypocaloric diet alone in middle-aged and older adults. In other words it increases the amount of calories you burn, also referred to as “resting energy expenditure”. 
In another study that measured the “resting energy expenditure” effect of water, discovered through microdialysis technique assessment on adipose tissue that drinking 500 ml of water increased metabolic rate by 30%. The increase occurred within 10 min and reached a maximum after 30-40 minutes. [3, 4]
It seems drinking cold water can also help increase the weight loss effect of water as it was discovered that drinking water that had been cooled to 3 C caused a small increase in energy expenditure of 4.5% over 60 min. 
Drinking water appears to stimulate thermogenesis, or heat production, in the body, particularly when it’s chilled. The body has to expend energy to warm the fluid to body temperature, and the more energy expended by your body, the faster your metabolism.
In a study of overweight women who drank over 1 liter (34 oz) per day. It was discovered that they experienced a weight loss of 2 kg (4.4 lbs) over a 12-month period. And this was achieved without any change in lifestyle except drinking water. 
In yet another study it was discovered that overweight females participating in the study who drank 1.5 liters of water showed noticeable weight reduction, body fat reduction, and appetite suppression. 
As stated above, water can play a positive role in regulating how hungry we get.
In one study it was discovered that Pre-meal water consumption reduces meal energy intake in older but not younger subjects. Hunger ratings were lower and fullness ratings were higher in older than younger adults. 
Drinking water keeps you hydrated and hydration has been associated with weight loss caused by decreased feeding and increased lipolysis.
And effect is clear and consistent in animal studies. 
“Thirst, which is triggered by mild dehydration, is often mistaken for hunger by the brain,” says Melina Jampolis, an internist and board-certified physician nutrition specialist. “You may be able to decrease appetite by drinking water if you are, in fact, low in water not calories.”
“This sends messages to your brain signaling fullness,” Jampolis says.
“When muscle cells are dehydrated, they break down protein (aka muscle) more quickly and build muscle more slowly, so your workouts are much less effective,”
“If your body can’t dump excess heat via sweating, you’re setting yourself up for heat exhaustion or worse,” she says. “Being adequately hydrated can improve your workouts by decreasing fatigue, which can allow you to work out longer and burn more calories.” 
Because water contains no calories it is important to have in mind that just drinking more water instead of higher calorie alternatives such as juice, soda, or sweetened tea or coffee can reduce your overall liquid calorie intake.
A study published in The American Journal of Clinical Nutrition showed that replacement of liquid calories with water after the main meal may lead to greater weight reduction during a weights loss program. 
So how much water should you be drinking? It all depends.
According to the Institute of Medicine (IOM), the daily water recommendation set, is a total of 13 cups which is about 3 liters of fluid each day for men. While for women it was a prescribed 9 cups, which is a little over 2 liters of fluid each day. 
But sometimes the body may need more than that. For instance on days that you sweat a lot due to exercise or other factors, drinking more water is the way to go.
“Older people don’t sense thirst as much as they did when they were younger. And that could be a problem if they’re on a medication that may cause fluid loss, such as a diuretic,” says Dr. Julian Seifter, a kidney specialist and associate professor of medicine at Harvard Medical School. 
Another study showed that women who appear to be adequately hydrated consume an average of approximately 2.7 liters (91 ounces) of total water — from all beverages and foods — each day, and men average approximately 3.7 liters (125 ounces) daily. 
My advice would be that you allow your thirst to be the guide and since it is all about drinking water to lose weight then drinking water before each meal should be part of your method. And when you feel hungry make sure you drink water first, to check if the hunger is really for food or for water.
So if you are among those drinking water to lose weight and still wondering if it is a legit weight loss practice.
Then the answer is YES!
But you should know that drinking water to lose weight should not be a stand alone practice. It works best with a weight loss program like diet and exercises.