As one who has been there; my non medical opinion ( read - you need good doctor here) is as follows:
If Liver is leaking bad, dropping metformin in my opinion is bad idea.
I am on insulin and agree with comments by other writers here. I hate glipizide with its extreme long strike ( time to live) that forces one to eat more to prevent bad lows.
Diet is key issue here; yes 500 calories is low but I run on 1200 calories a day and 1-1/2 to 2 miles walking/exercise a day and my take is that depending on energy burn 1500 calories a day can be way too much especially if liver leaking - throwing back way more glucose.
I would drop diet low initially and watch weight gain and excess glucose numbers and if lossing weight - increase calories slowly.
Just an opinion that needs validating with your Doctor/safety officer.
IN MY HUMBLE OPINION, FIXING t2 IS The FOLLOWING:
a) get diet and exercise in proper proportions as well as drop diet to low gylcemic with comment to add carbs up a bit if liver adds too much glucose when blood bg drops sub 70.
b) be sure sufficient exercise and energy burn. Critical.
c) identify medical misfires/issues - leaky liver, low producing/sleeping pancreas - add insulin as required. Fix misfires - metformin for leaky liver as well as check other hormones for improper performance.
What is not stated is that liver leaks and misfires can overwhealm good diet and exercise program and thus medical assistance will be key to resolving this mess.
Liquid Insulin is far more flexible allowing adding only that which is required as boost. Pills like Starlix/glipizide just hammer pancreas to dump in huge blast. And one has to eat to meet that generation.
But at all times check with your Doctor, I am just sharing my experiences.