I really hate when people feel the need to justify their orders to me by recounting their entire medical history. "I'm eating light because I've had diarrhea all day." "I had to go get bloodwork done today so I need to get my sugar up."
If it's not an allergy that you're alerting me about so I know to keep the garlic off your plate, I don't need to know and I really don't care.
My first TWO tables did this to me yesterday, back to back. Husband and wife come in, wife feels the need to expand on every interaction in the ordering process. "I'd really like to get a soup, but it would fill me up too much." "I wish I could eat anything I wanted like I was younger, that cheesecake sounds soooo gooood!" Etc.
The crowning moment was when her husband ordered an extra side of gravy, which is not out of the ordinary at all. But she felt the need to tell me "not to forget it, he needs a lot of gravy because he doesn't produce saliva." What? Is that a thing? And regardless, why did I need to be informed? I was going to bring you the gravy.
The second did the same thing, not to the same extent. She just spent five minutes explaining to me why she needed to replace her french fries with onion rings, because she was diabetic and couldn't have potatoes.
I understand wanting to make conversation, but there's a line, my dudes.