Have a look at the ingredients.
I use a chicken toothpaste to clean Harry’s teeth but he is not a diabetic. The brand I use is Petosan and I looked at the ingredients and I don’t think they have any sugar/carbs in it. If I were you I would email the company and ask them.
If you have never cleaned your kitties teeth before, I would start off with letting him smell the toothpaste then the next day rubbing a small bit on his teeth with your finger just to get used to the taste. Then gradually introduce the brush. Don’t expect him to just stay there and let you brush his teeth. It will take time to get him used to it. Just start off giving the teeth one brush and stop and telling him he is a good boy.try and keep it a positive experience.
Harry will just lie there and let me brush his teeth but I have been doing it since he was 6 months old. He is one nearly 5
It is well worth the effort as Harry has lovely white teeth with no bad breath at all. I left it for a few weeks once and just gave him bones to chew and was amazed at how slimey his teeth had become in a short time. I clean them last thing every night.