Okay, so my pancreas shut down on me a little over 7 years ago, and I was having a discussion with my husband about being thirsty. I have three children who are not diabetic and we went out to eat and my husband let them have a little bit of regular soda (they made little suicides). Later on, they were thirsty and I was like, “It was probably the soda!” And my husband looked at me funny. I was like, “well, if I had a sip of that or anything sugar I would be ravenously thirsty!!!” And he was like, “no, normal people don’t get thirsty like you do, their bodies produce insulin right away.” And I thought that was crazy! I can’t EVEN REMEMBER sugary things not making me thirsty, but I know I could have anything and drink anything like that and even a regular soda would quench my thirst sugar long before I had diabetes. It just struck me how completely different my life is now. I’m like the food police in my house, and I’ve even gotten in an argument with my mother in law over giving the kids too many carbs.
I try to eat low carb, but I’m not one to deny myself a treat here and there. I think it just makes me sad because even when I do have something that is sugary (on the rare occasion- cake, ice cream, etc.) it’s a very unpleasant sensation of being thirsty even when I’ve bolused for it!!! How this disease affects every. single. aspect. of. our. lives!
Ahh same thing happens to me. I try to eat low carb (did I say try??) but I do ocassionally have something sweet. It does make me extreme thirsty even when my blood glucose levels are under my targets.
I found this info, you might find it interesting 
When you consume sweet foods, sugar enters the bloodstream and begins to circulate through the body, according to Indiana Public Media’s “A Moment of Science.” These sugar particles funnel water from your body’s cells, depleting supplies. Your body’s cells then send chemical messages to the brain indicating that it’s time to consume additional fluids. Meanwhile, your brain routinely monitors blood concentrations to maintain normal levels. When the brain senses sugar overloads, that also triggers thirst.
I’m not sure I can speak to this intelligently, I feel like I’ve been thirsty my entire life. I haven’t eaten anything sugary since diagnosis in more than spoonfuls (I’ll have a bite of my wife’s dessert when we’re out to eat on a special occasion), and I eat very low-carb. What I remember from before diagnosis (and I wasn’t “prediabetic” or slow-onset Type 2 or anything, my a1c and fasting BG were in ideal range in 2015) was that I always had enormous thirst. If I had a regular soda at a restaurant with dinner, I wanted many refills. If I had water, I’d drink water constantly.
Pretty much still applies 
Speaking of which, I have to go fill up my Nalgene bottle with more water haha. Coffee (black) is making me thirsty…
So it’s very possible I don’t know what I’m talking, so take this with a grain of salt. My hunch is that eating a carb-heavy diet can make a person more thirsty, even without taking into account pancreas problems. From what I understand, the way that glucose is stored in muscles and the body is with four water molecules attached to it, so you presumably need to get those water molecules from somewhere. That’s why people who do a ketogenic diet and deplete their glycogen stores may drop weight very quickly – because a lot of that excess water used to store the glycogen is shed first.
Not sure if that’s related, however. I too find I need to drink a lot of water with carb heavy meals. I don’t have diabetes.
I think this is pretty well established. Once, years before I had diabetes, I mentioned to my doctor that eating salty foods made me thirsty. He said sweets would do the same thing. After pausing a moment to reflect, I said, “you know, you’re right; they do.”
Sweets never made me noticeably thirsty. These days, though, I am ALWAYS thirsty, so I can’t make a judgement call about sweets or anything else being the cause. My thirstiness seems to persist regardless of where my BG is or what I’ve eaten lately.
I don’t eat a lot of carbs normally, but maybe? I also wonder too if it’s “just in my head.” Like, there are obviously times when my BS is high or I eat something sweet and I am thirsty, but I also just wonder if my brain stays “stuck” in thirsty mode. No science, obviously, haha. Just curious. I did a lot of acting classes and theatre when I was younger and that was one thing we discussed quite often. If you do something often enough your brain “remembers” and you tend to do that thing even without thinking.
Sweets make me thirsty because I need to wash the “taste” out of my mouth. I enjoy the flavor at first but then like a bartender at 2am I’m like “everybody out”!
I have anxiety about other sensations though and have always chalked it up to that.