Hi Rosalie and welcome to the forum. Thank you foe fostering a diabetic kitty.
He is very young to be a diabetic but it does happen.
Lantus is a good insulin.
Until a diabetic kitty is regulated he will be hungry.
Was he underweight when he came to you? And is his present weight a good weight or is he stil underweight, or overweight?
Thee are a few things I can suggest but I don’t know how tied you are to doing what the shelter tells you to do.
FOOD
There are better options than the Hills dry you are feeding. Is it the MD or glucosupport dry? Almost all dry food is high carb so it would be better if you could move to a low carb canned food, especially seeing he is so young and he has many years ahead of him.
I can give you a list of canned foods that are suitable for diabetic cats that are not expensive and can be bought at the supermarket.
However it would not be wise to just swap over to a low carb diet unless you were home testing. That is because the lower carb food will lower the blood glucose (BG) and you would have to adjust the dose to stop him dropping too low.
I think you would be better giving him the same meal at the am and the pm shot time, amd then giving him 2 snacks in the am cycle and 2 snacks in the pm cycle around 3 and 5 hours after the insulin doses.
HOMETESTING
IT sounds scary but it is not, and the cat will not hate you. We can teach you if you like. Just let me know. You can buy a ReliOn glucose meter from Walmart very cheaply and the test strips are cheap as well. This would be by far the best option for your kitty as we could help you get the best dose for him, and get him regulated and not as hungry all the time.
FOOD CHART. Look for carbohydrates 10% or less. Many feed fancy feast pâtés.
HOW YOU CAN HELP US HELP YOU. there are several links within this link including a
hypo kit link. Please make sure you have one of those.
Please ask us lots of questions.
Bron