You can imagine several reasons why KFC has decided that its slogan, "Finger lickin' good", must bite the dust.
Hygiene would be a start. At a time when public buildings of all kinds, not just hospitals, are providing medicated hand gel to prevent the spread of infection, the liabilities of finger lickin' should be clear. You could also argue for dispensing with it on linguistic grounds, at least in non-American markets. British English doesn't do "lickin'", not even now when teenagers punctuate every sentence with "like". You might even, if you were a stickler for propriety, mention good manners. Lickin' your fingers is rather rude, especially if you don't have a napkin.
But to cite health as the reason for letting it go, after all these years of loyal service, seems perverse. How is "finger lickin' good" unhealthy? If it's good, it's good – as the replacement slogan "So good" will continue to insist. And you have to ask whether "healthy" will work for KFC.
Did anyone ever pop out for a bucket in the belief that they were contributing to their Five-a-Day? Whatever would cheery old Colonel Sanders have thought? Or is he about to go the way of the Michelin man and reappear in the new adverts all slimmed down?