@annalaix I doubt you're really that envious of his ability to eat fried foods - although it may feel like it because we often focus on the things we can't have so much more (which is one reason choice is so powerful for undoing the hold certain naughty things have on us).
Anyway the way I would go about developing choice where there may appear to be none is this:
What positive thing would eating fried food give me?
It would give me a feeling of X.
OK so what is another way of getting a feeling of X?
I could do such and such activity...
And what is another way?
I could do so and so...
Then you get the same outcome without the diabetic response.
You may get stumped at X...
It would give me a feeling of X....
Whats another way of getting the feeling of X?
Err I dunno...
OK what does a feeling of X give me?
A feeling of Y...
And what's another way of getting the feeling of Y ?
I could do such and such.
And what's another way?
I could do so and so...
And there's nothing stopping you going to Z and beyond...
well done, you now have behavioural flexibility and no diabetic response to contend with. It's not about the behaviour it's about the intention beyond the behaviour and there's always multiple behaviours that can satisfy an intention so you never have to feel out of choices (or envious).
Something like that anyway