The ASA received 63 complaints about 2013’s "last man standing" TV and outdoor ads created by Grey London, which claimed that Lucozade Sport "hydrates and fuels you better than water".
In a ruling published on Wednesday, Lucozade’s previous owner GlaxoSmithKline was rapped for deviating too far from the approved wording in the EU Register of nutrition and health claims, which came into force for UK advertising codes in 2012.
The ads adapted the claim of "contributes to the maintenance of… performance" to the single word "fuels". This meant consumers were less likely to understand the claim correctly, the ASA said.
Professor Paul Gately, the Carnegie professor of exercise and obesity at Leeds Metropolitan University and spokesman for the Natural Hydration Council, the bottled-water association that complained about the Lucozade ads, said they were "not supported by the scientific evidence for carbohydrate electrolyte solutions".
He explained: "Some consumers might not consider the term ‘fuels’ in the context of absorbing calories, which is essentially what it means. It’s up to Lucozade to articulate things properly."
The ruling follows a rise in ads breaching the health claims rules since the EU Register launched, from eight in 2012 to 12 in 2013.
A spokeswoman for Lucozade Ribena Suntory, the brand’s new parent, said: "[The new regulations] are quite complicated… We will ensure that future advertising is more aligned to the authorised claim."
In another ruling published yesterday, the ASA criticised the PepsiCo brand Naked Juice for exaggerating health claims about the benefits of antioxidants.
Guy Parker, the chief executive of the ASA, said: "Claims that aren’t [on the register] simply can’t be advertised. The dividing line between acceptable and unacceptable is not always clear-cut; even big players who invest heavily and well in compliance can get it wrong."