I am diabetic too. And this is the recipe I use and it doesn't seem to screw my bloodsugar up. But everyone is different depending on the stage and type of diabetes. The salt and sugar are less then most other brines in this recipe but it still makes a very good product.

1/4 cup pickling salt
3/4 cup Dark brown sugar
1 tsp onion powder
1 tsp garlic powder
1/4 cup Morton tender quick
1/2 gallon water
1 tablespoon molasses
2 tablespoons honey

Mix all ingredients in glass, plastic or stainless container.
Brine fish for 12 to 16 hours.
Rinse fish in cold water and dry with paper towels.
Put fish on smoker racks and let air dry for 1 hour.
Smoke the fish I use alder or an alder apple mix.