Nice to see a Vet reading the boards. I have little experience with diabetes so good information to read.
Hi Eddie
You should prepare 1/3 of the meal and offer it to your dog, once gone, inject the insulin then feed the remaining 2/3 of the meal
You can substitute homemade meals for whatever type of dog food you are feeding like chicken and vegetables for example.
I hope this is helpful and if you'd like to discuss further please call my veterinary office toll free at 866 372 2765 as I am glad to help further.
Thank you
Dr Carol Osborne, DVM