You know how whenever you’re thirsty and reach for an ice cold refreshing soft drink someone invariably tells you that soda will dehydrate you or only make you thirstier? Yeah, well it turns out that is total BS.
From the New York Times:
It was long thought that caffeinated beverages were diuretics, but studies reviewed last year found that people who consumed drinks with up to 550 milligrams of caffeine produced no more urine than when drinking fluids free of caffeine. Above 575 milligrams, the drug was a diuretic.
So even a Starbucks grande, with 330 milligrams of caffeine, will not send you to a bathroom any sooner than if you drank 16 ounces of pure water. Drinks containing usual doses of caffeine are hydrating and, like water, contribute to the body’s daily water needs.
A 12-oz can of Coke has 35mg of caffeine. So you’d need to drink 16 cans (1.5 gallons) in order to ingest enough caffeine for it to be the slightest bit dehydrating. Of course if you managed to drink that much Coke before any of the caffeine wore off you would be a champion–so you probably wouldn’t need to worry about little things like dehydration anyway.