You should Test/Feed/Shoot....we test to make sure they are high enough to get insulin, Feed to make sure they're at least willing to eat, and Shoot, usually with their head in the bowl.
Glargine doesn't usually start to "kick in" for about 2 hours, so as long as kitty is willing to eat, they don't need to eat a certain amount...as long as they'll eat a decent sized meal in about those 2 hours. It's not necessary to wait
as long as you know they will eat.
Also with Glargine, it usually takes 5-7 days to see how well the starting dose is going to work. Glargine is what we call a "depot" insulin. In simple terms, it's kind of like a time-release medication. Some gets into the bloodstream and the rest goes "in the depot" and slowly releases into the bloodstream....but it can take 5-7 days for the depot to be full so it's releasing the correct amount based on the dose.
How much did your vet say to start on? Most cats should start at 0.5 to 1.0 unit, twice a day.
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