Lose Weight by Drinking More Water

Drinking Water Can Make You Burn More Calories

Most of the studies below looked at the effect of drinking one 0.5 liter (17 oz) serving of water. Drinking water increases the amount of calories you burn, which is known as resting energy expenditure.

In adults, resting energy expenditure has been shown to increase by 24–30% within 10 minutes of drinking water, lasting at least 60 minutes. One study of overweight and obese children found a 25% increase after drinking cold water.

A study of overweight women examined increasing water intake to over 1 liter (34 oz) per day. Over 12 months, this resulted in an extra 2 kg (4.4 lbs) of weight loss — with no other lifestyle changes.

When the water is cold, the effect may be even greater: your body uses extra calories to warm it to body temperature.

Drinking 0.5 liters (17 oz) of water may increase the amount of calories burned for at least an hour. Some studies show that this can lead to modest weight loss.

Drinking Water Before Meals Can Reduce Appetite

Some people claim that drinking water before a meal reduces appetite. There seems to be some truth behind this, but almost exclusively in middle-aged and older adults.

Studies of older adults have shown that drinking water before each meal may increase weight loss by 2 kg (4.4 lbs) over a 12-week period. In one study, middle-aged overweight and obese participants who drank water before each meal lost 44% more weight than a group that did not.

Another study showed that drinking water before breakfast reduced calories consumed during the meal by 13%. Studies of younger individuals have not shown the same reduction.

Drinking water before meals may reduce appetite in middle-aged and older individuals. This decreases calorie intake, leading to weight loss.

Lower Calorie Intake and a Lower Risk of Weight Gain

Since water is naturally calorie-free, it is generally linked with reduced calorie intake — mainly because you drink it instead of beverages that are often high in calories and sugar.

Observational studies show that people who drink mostly water have up to a 9% (or 200 calories) lower calorie intake, on average. Drinking water may also help prevent long-term weight gain.

• Adding 1 cup of water daily may reduce 4-year weight gain by 0.13 kg (0.23 lbs).
• Replacing a sugar-sweetened beverage with 1 cup of water may reduce 4-year weight gain by 0.5 kg (1.1 lbs).

Drinking more water may lead to decreased calorie intake and reduce the risk of long-term weight gain and obesity, especially in children.

How Much Water Should You Drink?

Many health authorities recommend eight 8-oz glasses (about 2 liters) per day, but this number is arbitrary — water requirements depend on the individual. People who sweat a lot or exercise regularly may need more.

Keep in mind you also get water from foods and beverages like coffee, tea, fish, milk, and especially fruits and vegetables. A good rule of thumb: drink when you’re thirsty, and enough to quench your thirst. Based on the studies, 1–2 liters per day should be sufficient to help with weight loss.

• Liters: 1–2
• Ounces: 34–67
• Glasses (8-oz): 4–8

According to the studies, 1–2 liters of water per day is enough to assist with weight loss, especially when consumed before meals.

Take-Home Message

Water can be really helpful for weight loss. It is 100% calorie-free, helps you burn more calories, and may suppress your appetite if consumed before meals. The benefits are even greater when you replace sugary beverages with water.

That said, water is just one small piece of the puzzle — you’ll have to do more than drink water to lose a significant amount of weight.