A gradual change of food is necessary as the cats first have to get used to the new food composition. If the change is made too quickly, there is a risk of digestive problems, diarrhoea and flatulence. Ideally, the transition should take around two to four weeks. Small amounts of the new food are always added to the usual food, while the previous food is gradually reduced. This is done until there is only the new food in the bowl and the change of food has been successfully completed.