My DH has diabetes and I'm a podiatrist so we do a lot on diabetes because they make up a lot of our case load.
Not being mean, but they will find any way to sneak sugar into their diets. Having said that dh was given little diet advice but luckily I knew what to do (and diagnosed him and sent him to the gp).
Sugar is sugar, if she looks on the back of the pack it will tell her exactly how much of the carbohydrates in sugar is sugar. Un-refined sugar would be sugar beet or cane in its raw form, plantation owners with slaves had rampant tooth decay but slaves who ate raw cane didnt because it was ingested with plant fibre etc which slows down absorption.
Her HbA1c test will show up what she has done so it cannot be hidden from the gp she is caning it (no pun intended).
Another problem she has is in her interpretation of moderate. To me a treat is something I have when I have pmt, to dh its a daily reward to going to a job he hates. Gp might have been thinking one pudding a fortnight, def not two a day.
Some diabetics cannot tell when their sugar is too high so she might not feel ill with high reading anyway, but no one with type II diabetes eats a high sugar diet and maintains good control.
But, she is a grown adult and if a high sugar diet is worth her going blind from/.getting kidney failure/losing a leg for then there is little you can do. I know exactly how stubborn they are. I've met some who maintain control and most who bumble along thinking it will never happen to them.
Diabetes UK is an excellent resource for patients who need advice but dont forget their is a distinction between ignorance and willful mis-management.
The gp practice should have some free blood sugar monitors for patients but they are less keen these days to give them out as some patients take note of a high reading but dont actually do anything about it so the attitude now is to rely on HbA1c readings which the patient cannot lie about (diabetics lie all the time to us, I'm not above phoning a practice nurse to ask if Mr X has excellent control, the derisive snort down the phone tells you a lot!).
There is a product called sweet freedom which is in tesco and asda iirc, it is supposed to be a low GI product but when I emailed them to ask the gi reading they just said it is low gi so I didnt buy it.
A book on a low gi diet would tell you more about what she is eating, things like roast parsnips and white baguettes are surprisingly high gi.