Do you have any tips on transitioning my cat or dog to a new food? Some cats and dogs get an upset tummy when changing foods, but a gradual change helps prevent problems. Unless you have or are getting a prescription diet and your veterinarian says otherwise, the following schedule is a good help to transition your pet to a new type of food without problems: Days 1 and 2 – mix 3/4 of the old food with 1/4 of the new food Days 3 and 4 – mix old and new food half-and-half Days 5 and 6 – mix 1/4 old food with 3/4 new food Day 7 – give 100% new food If you see signs of problems during the week, slow down the transition. And of course, check on the new bags/cans how much your pet should have for its weight and level of activity. This can vary greatly depending on ingredients.