This is from Hi-Lo about 12 minutes ago. They have canned and plastic bottles of Glucerna.
The Hunger Smart are j$588 a bottle (price is probably wrong) and the canned shakes are supposedly $476.
My advice would be to stop at Mega Mart, or better yet, Progressive Foods in Fairview Mall just after leaving the airport and stock up on what you think you need there and use Hi-Lo in case you need more.
There are probably some Jamaican equivalent products, but I have no idea of their names.
Nevertheless, you are covered here man. No worries.