Aspartame - a sweetener commonly used in low-calorie soft drinks including Diet Coke - has been reclassified as a 2B carcinogen. But what does that really mean?

Diet Coke kills? Aspartame - and why we're so bad at understanding 'cancer risk'
Diet Coke addicts had a nasty shock in June as headlines exploded with warnings the the World Health Organisation was about to classify aspartame - a common sweetener - as "possibly" carcinogenic.  On July 13, the International Agency for Research on Cancer (IARC) - a branch of WHO - duly did so, upgrading aspartame from a category Three to a category 2B cancer risk, an eclectic field which so far includes 323 agents ranging from talcum powder and "traditional Asian pickled vegetables" to bracken fern, extremely low frequency magnetic fields, and carpentry/joinery.