If you're trying to lose weight and you drink over a liter of water every day, you might lose more weight—even if you're eating the same amount—because it helps your body manage insulin and stay hydrated.

When overweight people on a diet drink more than a liter of water a day, they tend to lose more weight—even if they don’t eat less—possibly because water helps their body use insulin better and reduces cellular stress.

If overweight people drink more than a liter of water a day while eating less, they lose more weight — even if they’re not eating fewer calories overall — possibly because their insulin levels drop and their body burns fat better.

Overweight young women who drink more water for two months tend to have a slightly lower BMI, even if they didn’t change what they ate.

When young women who are overweight drink an extra six glasses of water a day before meals for two months, they tend to lose a little weight, their BMI goes down a bit, and their body fat measurements slightly improve.

For people who are overweight, drinking a glass of water on an empty stomach can slightly boost calorie burning, but this doesn’t happen in people with normal weight.