We were feeding our cat and dog Blue Buffalo, which has a line of food that is grain free. Because Blue Buffalo is a little pricey, we switched to Taste of the Wild, which is another high quality food but lower in price. The only draw back to buying Taste of the Wild is that it may be difficult to find. I wouldn't suggest switching to Science Diet either, because it's main ingredient is corn. Here is a hub I've written about choosing quality dog food.