Everyone knows caffeine is a diuretic, right?
Don’t be so fast to flush that toilet… turns out that conventional wisdom is wrong. The latest science that… ummm… people who actually research the topic shows that consuming a caffeinated beverage has no more of a diuretic effect than… wait for it… water. As far back in 1928, caffeine was found to have no significant impact on output of urine. Later studies corroborated this, finding caffeinated beverages did not affect total volume or flow any differently than other beverages.
The Institute of Medicine found that “caffeinated beverages appear to contribute to the daily total water intake similar to that contributed by non-caffeinated beverages.”
So did the conventional wisdom become conventional? i.e. how did the wive’s tale get started? Basically, it seems the belief that caffeinated beverages increases your total urine output stems from research solely among people who don’t use caffeine. And indeed, if you are a caffeine virgin, i.e. you don’t consume caffeine, the old rules apply. Caffeine is a mild diuretic for those people who haven’t used it in a while.
On the other hand, if you’re similar to the significant majority of actual people who consume caffeine, then according to a bunch of studies and articles about studies, caffeine actually doesn’t increase the number of times you need to visit the loo.