The researchers based their findings on a survey of previously-published papers, many of which were tests on laboratory rats.

But of the 5,500 papers that were initially reviewed, just one or two—involving 500 people—suggested that diet drinks were better than water, and there was conflicting evidence even for this.

And yet this was the “take home” message from the study, said lead researcher Prof Peter Rogers from Bristol University, who has had funding from the UK’s Sugar Nutrition, which is supported by the sugar industry. In all, six of the 11 researchers had an association with the sugar industry, including two who were directly employed by sugar manufacturers.