"Participants in her study who were assigned drinks containing sucralose, a popular artificial sweetener, displayed no negative effects. But a cohort given the same drink with a liquid form of carbohydrate added — intended purely as a control group for the main study — showed signs of impaired metabolism, potentially leaving them vulnerable to problems such as weight gain and glucose intolerance.

Describing the unexpected finding as “a smoking gun”, Small said it suggested that recommending people with diabetes drink Diet Coke could actually do more harm than good if they consumed it with some types of food — such as french fries."