I am going through the exact same thing with Nellie for more than 3 months now! I have tried different foods, different proteins (kibble, cooked, raw) and it hasn't made much of a difference. She can go four days without comiting and then bam we are at it again. I've been to four different vets including an internal medicine specialist who seems to be my last option at this time because in the last week she has been comiting digested food while sleeping and almost aspirating on it! So back to the specialist tomorrow because I made the call to do some diagnostics on her to get to the bottom of this. It could be that they find nothing and I'll just have to live with it. I've written to two of the raw companies that I've fed her to see if they can offer tips. I've tried some great tips from folks on here but it's still a problem. I hope it's just a spell for your pup and not a long time thing like I've been dealing with. It's a real mystery. Also after trying so many different kinds of food, I think Nellie is tired and now refusing to eat even her favorite treats. Aargh! So my newest tactic is putting small bits of her raw food on my palm, spreading it out and letting her slowly lick it instead of inhaling it. She is still comiting though. But I'm confident that I'll get to the bottom of this. I'll keep you posted on my girl and let me know how things are with your pup.