How to Keep a Dog From Eating a Cat's Food. When you are raising a dog and cat together, many things come into play. You'll be busy separating the dog and cat toys, maintaining peace between them and keeping the dog from eating your cat's food.
Separate the food. You can feed your dog in one area of your home and your cat in another. Put up a gate to block the area where you have the cat's food. Choose an obstruction that the cat can get through with its more flexible body, but the dog can't.
Set the cat's food on a high surface that the dog can't reach. Cats can jump onto tables and counters the dog can't reach. You can pick a location besides the kitchen to put the food; it doesn't have to be a kitchen counter. A dresser in the bedroom, the bathroom counter or even on top of the washer or dryer will do the trick.
Buy a cat crate and put his food in there. It should be big enough for the cat to get in and out of, but too small for the dog to enter.