Than I guess it will be the raw diet for you.....not sure, but I think you may need to wait until the little guy builds up a better system.
We used to use a high end holistic dog food that we bought from Global, they changed owners or something and we found our dog at the time did not like whatever they did to the food, that apparently "never changed"...dog needed to go on a diet so the vet suggested a Hills diet food, we gave it a try, Burton liked it and he lost the extra weight gradually, than moved him to a senior food.
Our puppy went on Hills puppy, once he git over his sensitive stomach issues....he is now on Hills J/D, which he likes a lot.