It's almost impossible to know if this might be useful without a considerably detailed description of your current behavior. So this is just a shot in the dark, to give you something to think about.
The tonicity of gastric contents can have a lot to do with the rate at which it moves through the various stages of digestion. And that's going to be intricately linked with the body's existing fluid dynamics to "normalise" anything there that's "too much" or "too little" of the state it needs to be in to digest "normally", and consumption of anything less tonic than the food that's being digested.
https://www.google.com/search?q="Gastroparesis"+"hypertonic"
Stethoscope's are dirt cheap and the circulatory isn't the only thing that can be heard. So you could buy one and do some structured self experiments. Listen for slow contractions of the fundus of the stomach and faster contraction waves in the the antrum over the course of several hours. Vary preexisting fluid balance, anything you're adding on top of digesting food, note the changes and find the patterns.
I haven't done this for a while but found it utterly fascinating when I was in to it. It was like I could behave in a way that would paralyse the process, a way that would speed it up far too much, and a way that resembled a happy medium. And around that, my whole sense of wellbeing could change.
