Hi, immortal flower (such a pretty2 name!)
Here are so sites for you:http://www.catclub.net/cat_care/introducing.asp#Feeding
The amount of food you should feed your cat depends on the cat itself, as each cat eats different amounts of food. As a rough guide an adult cat will eat about one tin of cat food, served at room temperature spread over two meals a day (400/450g). A cat has specific nutritional needs, so his diet must be balanced.
Is obesity a problem in cats?
Generally cats are able to regulate the amount of food they eat and it is uncommon for them to become too fat. However, if large quantities of tasty food are always available they may start to overeat and older, neutered cats that spend most of their time indoors are most susceptible. Weigh your cat regularly to make sure it is not gaining or losing weight and adjust the amount of food accordingly. To weigh your cat first get onto the scales yourself and record your weight, then pick up your cat and record the weight of both of you, finally deduct your weight from the second reading to find how much your cat weighs. Alternatively cats can be weighed in a carrying basket but remember to allow for the weight of the basket when calculating its weight. If your cat needs to lose weight your vet will be able to recommend a special low calorie diet but do not attempt to put your cat on a 'crash diet' as this could be very damaging to its health.
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