This has come up loads of times before, the best thing to do is to see how much your cat wants to eat, and it does depend on what kind of food - if I give one of my fosters pouches, he will wolf one and ask for a second, if I am using tinned food, I Can use one tin between the four of them, despite one pouch and a 1/4 of a tin both being 100g. For my own cats, I give half a pouch and if they wolf it and are still hungry, they get the other half. Some days they do, some they dont.