I recently came across a study into caffeine consumption of 57 countries that examined the role caffeine plays in our diets and revealed what caffeine source each country prefers. The study, conducted by researchers in the Department of Preventive Medicine at Northwestern University Feinberg School of Medicine (Chicago, Illinois), used 2017 volume sales of caffeine-containing beverages (CCB) from London-based global market intelligence firm, Euromonitor International.
