You’ve heard all your life that for health and hydration, it’s necessary to consume eight glasses of water a day. If you drink your eight on a particular day, but instead of water, you switched things up a bit and had four glasses of water and four glasses of coffee—have you met your quota?
Coffee lovers rejoice, because… Yes — you have!
But about drinking eight cups a day… that’s pretty much a myth.
In an interview with the Wall Street Journal, Eric Rimm, a professor of epidemiology and nutrition at Harvard’s’ T.H. Chan School of Public Health, revealed that there is no set amount of water a person must drink each day — for several reasons: foods contain water; climate is a factor; people sweat differently; and body mass index is different from person to person.
All of those factors weigh in on how much water a person needs. Some need more. Some may need less.
But the real news here is this: If your body is telling you it’s thirsty, reaching for a cup of black coffee can be just as hydrating for you as choosing a cup of water.
Despite coffee’s ill-gained reputation as a diuretic, it’s actually a great alternative to water when it’s unsweetened, because, “it is almost without calories,” says Prof. Rimm. Therefore you’re getting just about all water when you enjoy black coffee. Plus, it’s been documented that regular coffee drinkers build up tolerance to the diuretic effects of coffee.
Need more proof? How about this: A British study last year involving male subjects found there was no difference in hydration status during two trials where the participants drank either water or coffee. The researchers hypothesized that when ingested in moderation, coffee would contribute to daily fluid requirements and would not result in progressive dehydration.
So go ahead and enjoy a thirst-quenching cup of java if you prefer it over water, and enjoy the many added benefits of coffee consumption including abundant polyphenols—micronutrients that are proving to have a strong role in the prevention of degenerative diseases, like cancer, high blood pressure and cardiovascular disease. Coffee can even boost your workout.
One word of caution: If you’re affected by caffeine content, you may want to switch to decaf to avoid the jitters. But as long as you enjoy a well-rounded diet high in fruits, vegetables and healthy fats, Prof. Rimm believes, “There is no reason to think that someone who solely drank coffee would have any issues.”
