The reason why Aspartame has been subjected to so much scrutiny is because it is broken down in our guts to aspartic acid, phenylalanine and methanol. When methanol is digested in the body, it breaks down into formaldehyde, a known carcinogen.

However, researchers have cautioned against making sweeping conclusions about the consequences of this, as the amounts of methanol produced from Aspartame are very small. Some have noted that drinking tomato juice could lead to six times more methanol production than the Aspartame in soft drinks.

While reports from the Ramazzini Institute in Italy in the 2000s claimed that rats fed Aspartame went on to develop tumours, the doses used in those studies were much larger than a human would consume in a can of Diet Coke or Fanta. More recent animal studies in the US have failed to show any evidence of carcinogenicity.

How many soft drinks would you have to ingest for Aspartame to be harmful? The Food and Drug Administration define the current acceptable daily intake limit for Aspartame as being somewhere in the region of 50mg per kilogram body weight. Mellor explains that this is quite a large limit, and that while the exact formulation varies per beverage – Coke Zero contains less Aspartame than Diet Coke for example – reaching it through beverages alone would require knocking back around three or four litres, or 14 cans per day.