The UK Advertising Standards Agency (ASA) asked the cereal maker not to show the television advert after finding that the research behind it was not 'robust enough' and the claims it contained were 'misleading'.
Kellogg's, in common with many cereal companies, is keen to promote ready to eat breakfast as a healthier option in the face of consumer concerns over high salt, sugar and fat levels but recent debate over advertising children's products has fuelled calls by industry bodies for more severe restrictions to be put in place.
In the advert, two schoolboys are compared - one eating Kellogg's Cornflakes for breakfast and the other nothing - and the child eating Cornflakes appears more energised and alert.
The accompanying words claim: "Research shows that when they eat a cereal like ours, kids are on average 9 per cent more alert."
Followed by the sentence: "Alertness measured by parents, comparing 63 children eating Kellogg's Corn Flakes to 34 children skipping breakfast."
But an independent expert enlisted by the ASA disagreed with the legitimacy of Kellogg's research. While the benefits of eating breakfast were not disputed, it was suggested that a more appropriate test would be to compare children who ate Kellogg's Cornflakes with those eating their normal breakfast.
The ASA said: "Although the study did show an increase in levels of alertness, it did not conclusively show that this was due to the cereal."
In addition, the Kellogg's study only monitored children for 30 minutes after breakfast whereas the advert gave consumers the impression that the effects would be maintained throughout the morning.
Kellogg's, who own children's cereal brands such as Frosties and Coco Pops, said the claims in the ad had been scientifically supported and quantified by two robust scientific studies which had shown significant increases in alertness after eating a high carbohydrate cereal.
According to market researchers TNS Worldpanel, Kellogg's is the UK's best known brand and had sales of between £530m (€781.8m) and £535m (€789.2m) in the past year.