For some cats, it causes constipation
I switched from Royal Gastro to Royal Sterilised because I thought it would help prevent weight gain after sterilisation.
With Royal Gastro, my cat had normal stools, but after 3 weeks of eating Royal Sterilised, she got constipated and didn’t poop for a few days.
It was sorted out with Lactulose and Royal Gastro Fibre Response wet food.
So, the low fat content in the Sterilised food can cause constipation in some cats (not all of them).