Why Water Helps Weight Loss (and Prevents Fainting, Too!)

New studies have found that drinking water can promote weight loss, and may prevent you from fainting after giving blood.

Magazine covers are always blaring about some “miracle juice” or another that can help you drop all of your unwanted weight. The truth is, you won’t find a drink more magical than plain old water—and now it’s got science on its side.

In a recent study from Vanderbilt University Medical Center, researchers found that drinking ordinary water can increase blood pressure in patients who are unable to regulate it naturally, and it is able to increase sympathetic nervous system activity and constrict blood vessels in all subjects.

Because it increases sympathetic nervous system activity, it also increases the amount of calories your body burns, which helps you lose weight. Sure, it’s not a dramatic amount—but when the only exercise you’re doing is lifting a glass, it’s pretty effective.

“I calculated it might be as much as five pounds a year if you drank three 16 ounce glasses of water a day and nothing else changed,” Vanderbilt professor David Robertson said.

If you’re swapping water in for a high-calorie soda, though, you’ll be cutting back your calorie intake dramatically, and could lose a significant amount. It’s a simple swap that could really help your health.

And in other water-related news, the American Red Cross has found that when blood donors drink a 16-ounce glass of water prior to giving blood, they’re 20 percent less likely to faint. It’s a discovery that could save thousands of lives by keeping donor blood in strong supply.

“If you pass out after giving blood, you pretty much never give blood again,” said Robertson. “If we can reduce fainting by 20 percent, we can reduce the unpleasantness of passing out and really bolster the number of people who can continue to be blood donors.”

So, who wants a glass of water?