McDonald’s changes the recipe for one of its most iconic menu items

Tweaking the formula for a much-loved dish can often cause more harm than good.

Coca-Cola found this to their detriment when they launched New Coke, suffering a hit to sales before Coca-Cola Classic made its triumphant return. And McDonald's have gone down a similar route with their Egg McMuffin in the US, giving up on the 'margarine instead of butter' experiment...with fantastic results. According to Fortune, sales of the popular breakfast item have increased by more than 10% since the decision to ditch margarine earlier in 2015. You might say it's a case of butter the devil you know...