You should think about not only what kind of food, but how to feed! My neighbor has a dog that should be in the 25lb weight class and he weighs, now about 65lbs, looks like a inflated dog or a pig on small legs. Alot of people like to keep the food bowl full at all times so the dog can nibble when ever, myself I figure out the right amount for my size dog (also take in to consideration how much treats you will be giving daily), and divide it by two and give in the morning and the rest in the evening. I like dry food because it is better for the teeth, unless you will brush your dog everytime it eats soft food. I have a career in dentistry that is why the teeth and gingiva are so important to me. Pick the dry food you feel comfortable with, but I like to add some beneful the healthy weight that has vegatables in it, twice a week. I add some to there regular food by removeing a portion of the regular food. Yes I know dogs are not vegetarians, but a little added to the carnivores diet is a good practice. I do brush my dogs teeth, and inspect there teeth every other morning as time permits. good Luck!
