A:In a word, no. Many people believe that drinking cold water burns more calories than room-temperature water—and while that may be technically true, the difference in calorie burn is minuscule, at best.
"The hypothesis is that if you drink cold water, the body has to warm it up and you'll burn calories and therefore lose weight," says Beth Kitchin, PhD, RDN, professor of nutrition sciences at the University of Alabama Birmingham. "But the tiny amount of extra energy your body expends really isn't relevant to any real-life applications." According to the University of Arkansas for Medical Sciences, you'll torch a whopping eight calories warming up a glass of ice water—about the equivalent of a small pickle.
Then there's the idea that drinking hot or warm water is gentler on the body and boosts digestion—a notion popular among cleanse enthusiasts. (Often, detox programs suggest adding lemon, cayenne pepper, and honey or maple syrup to make a sort of herbal tea.) But, as with most commercial detox claims, there's no good evidence this one is true either, says Kitchin.
One thing water temperature can help with? Palatability. "You're probably more likely to drink water, and more of it, if it's cold and refreshing," says Kitchin. Plus, drinking cold water while exercising on a hot day may even lower your core temperature slightly and help you keep your cool. Better yet, try an ice slushie: A 2011 study found that runners who drank them before running didn't get exhausted as quickly as those who didn't.
Bottom line: "The most important thing about water is that you're drinking it—not what temperature it is" says Kitchin. Not a plain old H2O person? Add a squirt of lemon, a slice of cucumber, or low-calorie flavor enhancers like Crystal Light powder or Nuun electrolyte tablets.