A study on habitual male coffee drinkers has shown that drinking 4 cups of coffee per day has a similar hydrating effect as water. (3)
Another study showed that taking 4-6 cups of black tea (equivalent to 168 – 252 mg of caffeine) had the same hydrating results as drinking the same amount of water. (4)
However, people who have not been drinking tea, iced tea, coffee or other caffeinated drinks for some time (days to weeks depending on a person), react temporarily to high amount of caffeine.
It has been found that, in these cases, drinks with large doses of caffeine (250-300mg which is about double of a standard, but strong coffee) can increase urination.
This increase, however, is only a temporary reaction to caffeine after long abstinence. Once the body accustoms itself to regular coffee intake of standard caffeine contents, the water loss from the body is insignificant. (1, 2)
Popular drinks contain various amounts of caffeine. Here is a breakdown of the standard amount of caffeine in most popular drinks and chocolate. (5)
Caffeine contents of various foods and drinks
|Coffee (5 oz. or 150 ml)||60-150|
|Tea (5 oz. or 150 ml)||40-80|
|Green tea (8 oz.)||15|
|Red Bull (8 oz.)||80|
|Soft drinks such as Coke/Diet Coke/Pepsi (12 oz.)||30-55|
|Dark chocolate 1 oz. (28g)||20|
|Hot chocolate (5 oz. or 150 ml)||5-20|
Is decaf coffee dehydrating?
The myths of coffee or tea being a diuretic exists because caffeine was believed to cause increased urination.
Decaf coffee contains very small amounts of caffeine so there are no reasons to think that decaf coffee is dehydrating.
NUTRITION FACTS VS NUTRITION MYTHS
You will find a summary of the most common nutrition myths and evidence-based nutrition facts here.