King Gustav III of Sweden (1746–1792) was convinced coffee and tea were bad for human health, and he commissioned the first "twin study" to prove it.
Gustav agreed to commute the death sentence of identical twins provided one drank three pots of coffee a day, and the other drank three pots of tea a day, for the rest of their lives, which he assumed would be short and miserable..
In fact, the coffee- and tea-drinking twins outlived King Gustav and the two doctors he assigned to conduct the experiment, with the tea drinker dying first at the age of 83.
Today, Sweden has the highest coffee caffeine consumption rate in the world at 388 mg of coffee caffeine per day as compared to the US (143 mg per day) and the UK (92 mg per day).
To put it another way, the average Swede consumes over 10 kilos of coffee, per person, per year.