Sensitive stomach in senior dog getting worse

Hello! My dog, Finn (Yellow Lab, 10y/o, male, neutered) has been a chronic puker his whole life. We’ve been through all the tests and trials to figure out why but never came to a diagnosis. We’ve managed it pretty well by feeding him soaked/softened Natural Balance kibble, no human food, soft treats, etc. Over the past few months his stomach has seemed to be overly sensitive; if he has anything outside of his kibble he gets sick (vomiting, normal stool). The past couple of days he’s occasionally not finishing his food which is not like him. My assumption is that he’s associated it with his upset stomach.  I'll be getting him to the vet to make sure that nothing more serious is going on, but in the meantime I’m wondering if it’s time to switch him to a different type of food. My question is: is there a recommended food for senior dogs with sensitive stomachs? Should we switch to wet food instead of soaking kibble? Or, is switching his food more likely to cause more harm than good at this point? Additionally, with him being less interested in his food, is this more of an emergent situation / does he need to be seen asap? Thank you!!

Hello - and thankyou for that excellent history and question.  Finn's situation does appear to be getting progressively worse, so attempts to pinpoint the cause and / or treat the symptoms do sound to be merited.  Things that your vet may want to rule out include pancreatitis, a low-level inflammation of the pancreas that leads to chronic nausea; this can be ruled out with slightly specialist bloods.  Liver disease, cancer, kidney disease, diabetes and hypothyroidism may be other possibilities.  A lot of vets will specify a bland diet at this point, in order to reduce any reaction of the stomach lining as much as possible.  Regarding how soon Finn might need to be seen, this could depend on how much fluid he is losing and how well he is maintaining his hydration; your vet might want to triage the situation, especially if there is a potentially long wait for an appointment.   Please will you let us know how he gets on?