How much dog food a dog should eat every day depends on the age and size of the dog. Large dogs eat twice as much as small dogs. Dogs under five kilograms should not eat more than 100 grams of dog food every day. 10 Dogs under 25kg should not eat more than 200g of dog food per day, and dogs under 25kg should not eat more than 400g of dog food per day. It is best to feed small amounts multiple times and do not give your dog too much each time.