If You Drink More Water, Will You Lose Weight?

Could carrying around a bottle of water, like the grown-up version of a sippy cup, make you slimmer? A study done in Berlin and another more recently by some of the same researchers claim that downing 16 ounces of H2O a day boosts metabolism by 24% to 30%. Impressive? You bet. But before you buy that BPA-free, high-tech water bottle, (there’s even one with a sensor that tells you when to sip) consider this: Nobody’s been able to replicate these results, say scientists who tried. The best they could get? Extremely cold water might raise your metabolism by 4.5% for a few minutes.

But even if drinking water doesn’t up your calorie burn, it can still support your weight loss efforts. Here’s how:

Switching from sugary drinks to water could slash your calorie intake by up to 9%. If you regularly drink sugar-sweetened sodas, teas, or fruity beverages, this one swap could save you 203 calories per day. This switch may be more powerful than cutting food calories, simply because it’s so simple and won’t leave you feeling hungry, say researchers at Johns Hopkins.

Sipping 2 cups of water before a meal could make you eat 75 to 90 calories less. Putting some zero-calorie ballast into your tummy 30 minutes before you eat takes up space, so you feel full faster, say Virginia Tech researchers who recently analyzed dozens of studies on water and weight.

Sipping an extra 4 cups a day could help you lose 5 pounds this year. That’s how much weight women lost when they increased their water intake or replaced soda with water, University of North Carolina at Chapel Hill researchers discovered after checking the water-sipping habits of overweight women on various weight loss plans. And only water helped; diet drinks didn’t, perhaps because it’s so easy to pair calorie-free sodas with high-calorie burgers, fries, and pizza.

So how much water should you drink? Experts say the old “eight glasses a day” rule has no scientific basis. Letting thirst be your guide is usually all it takes to meet your needs. Plain water and the liquid from other drinks (tea, coffee, fruit juice, milk) provide 80% of the water you need; the other 20% comes from food. Water-rich edibles include watermelon (no surprise!), tomatoes, cucumbers, and strawberries. Like water, these foods fill you up, not out. How do you know you’re drinking enough? Your urine will be pale yellow.