I've never bothered to tell any of the in laws that I'm diabetic. It just hasn't seemed worth it.
Oddly, it has been more important to tell my colleagues at work!
But then, we rarely eat with the in laws...
I told my parents. And all my friends.
So I got a box of Thorntons from a sis in law. I don't really like them. So wouldn't have eaten them pre-D. No worries.

I can re-gift.
My friends and colleagues who all know (and care enough to) give me 70% dark.


And Mr B gave me a box of Heston's divine chocs. Had some last year, and think they are the best and nicest I have ever tasted. No one else is going to get a look in. One a day. As dessert.
I do find the whole 'just one won't hurt' idea bizarre.
If someone told me they had lung cancer, I wouldn't give them a pack of cigarettes.
Or buy a drink for an alcoholic.
The words 'just one...' would come over as blindingly offensive, wouldn't they?
I know those are extreme examples - and not very appropriate - but it does depend how great your carb addiction, doesn't it?
And why do the gifts have to be food?
There are whole aisles of shops devoted to toiletries, accessories, hobbies... Heck, I LOVE a good gift voucher! It hardly takes a big effort to avoid food, does it?