Yes if his BGs are high then he will be ravenous because insulin is the key that unlocks the door to the cells of the body so he can use the food he is eating. Without enough insulin his body can't properly use what he is eating.
My entire gang of 14 which includes 2 diabetics eats 4 times a day, or basically every 6 hours. I basically feed them breakfast, lunch, dinner and a before bed snack. The before bed snack goes down at 10pm but is put down frozen so they can nibble on it as it thaws.
Although when I first adopted my two diabetics as diabetics I free fed them Friskies Pates, I would just put 1/2 a can mixed with water in their bowl and when it was empty refill it, making sure to pick up any that was left 2 hours before their preshot tests so I could get a true reading that wasn't food influenced.
Mel, Maxwell, Autumn & The Fur Gang