Yes you can provision in Bequia (note the spelling), but you will be limited.

In Bequia there are 2 Knights stores and of course Doris' Fresh Food for groceries. Doris' carries products from the US, Canada and UK that are hard to find in the Caribbean. However, you will pay dearly for anything you buy at Doris'!

The 2 Knights stores in town have groceries but you will be limited as to the brands you are used to. There is an outdoor meat seller, usually on Friday, on the street going up to the one Bank in Bequia.

Fresh vegetables are sold in Bequia but again, the selection is fairly limited based on what is available and the season.

You won't starve grocery shopping in Bequia but I would suggest you stock up with everything you need in Grenada, before you sail north. Grenada has everything you need at the IGA in Spiceland mall.