The ad, created by JWT, received three complaints from viewers who challenged the claim that Special K Sustain "contains extra protein and fibre", because the product contained less protein than Special K original, with which they believed it was being compared.
The TV ad featured a woman making a presentation in a meeting room and losing concentration as she imagined that the diagram she was pointing to was a real pie. The woman then imagined that the dots on the dress of a colleague had turned into cakes and a female voiceover said: "If you've only got one thing on your mind before lunch, you should try new Special K Sustain."
The ad then featured the woman at home having a bowl of Special K Sustain as the voiceover continued, "Delicious new Special K Sustain contains extra protein and fibre. See if it can keep you satisfied for longer."
Kellogg defended the ad by submitting evidence that compared the level of protein in each serving of Special K Sustain with nine comparative leading value sales cereal brands, including Special K original.
The advertising watchdog noted the evidence provided by Kellogg showed that a 40g serving of Sustain contained more protein than 30g servings of the original and other leading cereal brands, but considered that the extra amount could be provided by the larger serving size rather than the make-up of the product itself.
Kellogg also provided evidence that compared Special K Sustain with other cereals on a consistent serving of 30g, but took the average protein content from across all the other cereals including Special K original.
The ASA considered that consumers would expect a comparison to be made on a like-for-like basis and understood from Kellogg's documentation that a 30g serving of Special K original contained 4.5g of protein, more than the 4.2g of protein provided by the same serving of Special K Sustain.
The Advertising Standards Authority concluded that the basis of the comparison was unclear and that the phrase "contains extra protein and fibre" was misleading. It told Kellogg not to broadcast the ad again in its current form.