Defintely do not go back to the Fromm's pork and apple Sauce, if you think that was the culpritt. I had a scenerio with Rocky when I first got him, He wouldn't eat for 4 days, I took him to the Vet, The problem as it turned out was from going to what the lady had fed him before, which was Purina Large Kibble, and I gave him Purina small Kibble, but there was some other changes in the food as well, I didn't match it exactly, had a huge problem. I fed Rocky Rice and juice, or attempted too, with Hamburger, or with chicken, heck I tried everything, including hand feeding, he didn't want anything. I took Rock to the vet, The vet gave him some medicine to calm his stomach, I gave him that 2x a day for 4 days, all in while, Providing him Rice with hamburger mixed in, trying to get him back to eating, when he started eating, he went straight to Blue Buffalo Sensative food Kibble, No Grain. He did well on it, but still didn't have his appetite, for a long while I had to hand feed, and try everything to get 2 cups of food down him a day, 1 cup in the morning, 1 cup in the evening. When I adopted Rambo, Rambo was on Blue Buffalo Salmon Kibble, heres the funny part, I went to Pet Smart and picked up 24 lb bag of Salmon for Rambo, when I got it home, I put it in the pantry unopened, and continued feeding Rocky his blend, any time the pantry was open, Rocky would attack the Salmon bag of food, trying to get it open etc.... When I had Rambo Home, Rocky wanted nothing to do with his Sensative food, but wanted the Salmon, so I waited until the bag was nearly empty, and started the 3 days of 75% old 25% new, then 50/50 for three more days, then 75%/25% old, finished the bag, and went straight to 100% Salmon, Rocky I swear inhales the Salmon, and so does Rambo, when they finish eating, they exchange bowls and lick the left overs, dust I guess, but anyway, both are on the same Kibble, and the Salmon is so good for their coats, plus I use a couple of squirts of Salmon Oil in the morning feeding for them both, plus the Blue Buffalo Salmon Mix, Grain free is a 6 star food. I think if I were you, I'd continue the rice and meat your using, and transition your baby into the kibble you want to use, and transition him slowly, to make sure it has no ill effects on your baby. One more thing I want to mention, is it usually takes a while for the food your using to show ill effects, most of what I've read has been 4-6 weeks to get all the old out of the system, and really see the effects of the new, unless it's an allergy or something. So seeing it show up so shortly, really surprises me. Anyway, in my opinion only, and I'm sure many others will have some better ideas, or have been through exactly what your describing and will add to this thread, is a slow transition from what he's eating now. to his new food, again remember their stomachs are very sensative, I found this out day 1. The other thing I want to mention here, and I'll tag the other two that I had this conversation with, @Baconatoratar and @JAKEISGREAT, waking up in the morning on an empty stomach will also cause a vomitt of sorts, white-yellowish flymm, So what Bacanator suggested, was plain Rice cakes at bed time, at least they have something on their stomach, a light something to get them through the night till morning feeding. It's worked for me, and for them, just another idea. Hope this helps.