We just did two trips back to back. I informed both PD's after receiving their email, as well as when we got on the ships that my husband had food allergies, and then met with the restaurant manager. He promptly got his sheet out and showed me he had my husband's information I gave to our PD's. At each lunch or dinner meal, he was told he would be receiving a special dish if what was served as his selection would not be good for him. E.g., if he chose the chicken, but it had cream sauce, his sauce was made separate and without the ingredient. That goes for all the appetizers, second course, and desserts as well. The waiters told him at the beginning of the meal most of the time what he would get instead. Once at breakfast he took a roll that had walnuts on the top. It was not evident that walnuts were the "trimming". The waiter assigned to our table immediately told my husband he should not eat that roll, and he was able to get another. The breakfast buffrets,for my husband,had plenty of items he could choose from that fit his dietary needs. This was the case on the river ship, small ship, and hotels. During included lunches or dinners, the PD had arranged for a special meal or at least asked my husband if what was to be served was okay. Even the home hosted meal was made special for my husband's diet. When creamed soups were served, he was served the same "creamed soup' made without the cream. If small bits of cheese were served, his serving had a substiture. He is diabetic II as well, but diet restrictions are not an issue with him but food allergies are.
Having said all that, in the past, river ships especially, even telling the waiter or managr and PD, he would never be given a clear broth soup instead of cream soups. We just about gave up, but I started also asking the GCT booking consultant to have the diet requiremtents in the reservation notes. Since then it's been much better.
As for airline food, when he was first diagnosed with Type II diabetes, we were goiing on an overseas trip from Asia to US very soon. We ordered diabetic food. He said never again. He'd eat whatever he could from whatever he was served before he would order diabetic on a flight again. And he has stuck with this. If he cannot eat an item on the tray, he will eat what he can; he doesn't eat much while traveling on a plane anyway, so it's no big deal for him. His readings are well within the range so he doesn't worry.