Last Updated May 31st, 2019
You might think drinking a gallon of water a day – 128 ounces – would be incredibly difficult to do. After all, that would be 16 eight-ounce glasses of water. But if you spread it throughout the day, you’ll probably find that it’s actually not that hard.
And there’s a growing amount of evidence that doing so may help you cut calories and lose weight as a result.
Here’s what the science says regarding drinking water and dropping pounds.
How Water Can Help You Burn Calories
Research indicates that drinking water can help you burn calories and stay hydrated. It increases your “resting energy expenditure,” which basically means the amount of calories you burn without exercise.1 One study showed that an adult’s resting energy expenditure increases by as much as 30 percent for a 10-minute time period after consuming water.2
But the benefits aren’t limited to adults. According to the results of another study, obese children increased their resting energy expenditure up to 25 percent more after they consumed cold water.3
Another study showed that overweight women who drank as little as 34 ounces of water a day lost about four pounds more than women who didn’t drink water. And these women didn’t exercise. The only lifestyle change they made was to consume more water. The same study indicates that people burn about 23 calories for each 17 ounces of water they drink. This can definitely add up over time.4
Other studies show that people who drink water can substantially reduce their percentage of body fat.5
Reducing Your Appetite
There is evidence that some people who drink a glass of water before mealtime aren’t as hungry. This is primarily the case for adults who are either middle-aged or senior citizens.6 Older adults who drink water before a meal could lose as much as four pounds in three months, according to one study. Compared to a group of participants who didn’t increase their water intake, a group of obese middle-aged people lost more than 40 percent more weight when drinking water before each meal.7
And drinking extra water before main meals may also have weight loss benefits. In one study, researchers found that obese women who drank water before eating breakfast, lunch, and dinner saw a nearly 15 percent reduction in the amount of calories they ingested.8
Lowering Your Intake of Calories
If you like to have a sugary soft drink with meals, that’s a lot of extra, empty calories. Try drinking a glass of water instead. Water is calorie-free. According to the results of a study, people who usually drink water with each meal consume as much as 10 percent fewer calories at mealtime than those who don’t.9 Over the long term, drinking water instead of soda with your meal can go a long way toward helping you avoid gaining weight.10
There is also evidence that putting bottled water in your child’s lunch box each day could help them avoid becoming obese.11 Schools in two German cities implemented a program aimed at reducing obesity rates. Water fountains were installed in 17 schools, and children were educated on the importance of consuming more water. After one year, according to the results, the children’s obesity risk was reduced by 31 percent.12
How Much Should You Drink?
Drinking a gallon of water a day could help if you’re trying to cut weight. But the amount of water different people need often varies. If, for example, you exercise a great deal, you might need more than someone who largely lives a sedentary lifestyle.13
Other Benefits of Drinking Water
If you don’t stay hydrated, you run the risk of suffering many different types of health issues. For example, studies show that water could help reduce symptoms in people who are dehydrated and suffer headaches.14 And carbonated water may help people suffering from constipation and upset stomach.15
There is also evidence that consuming water could help lower the risk of a recurrence of kidney stones. The reason is that water helps increase the volume of urine that moves through the kidneys. This, in turn, dilutes the amount of minerals and reduces the chance that they will crystallize and form stones.16
The Final Word
As you can see, there is a great deal of solid scientific proof that drinking several ounces of water per day can help you in many ways. Water consumption may help you lose weight, but it also provides additional benefits as well. Not sold? Start out with a few extra glasses of water before your big meals, and see if you find yourself eating less. By adding a gallon of water a day to your routine, you’ll be well on your way to a healthier new year.