As far as food goes- since you are going there for the first time- i'd say see how much space you have left after you have your clothes, personal items, toilteries, school supplies, shoes, few kitchen stuff (plates, silverware, a pot and a pan, bowl...). Once you know how much space you'll have then start thinking about food items that you just have to have. In grenada- you could get most of the stuff- more expensive and you may not get the brand that you prefer. I always took cereal, and snacks, and took some homemade indian snacks and ready to eat things (the ones where you just have to microwave it and its ready) and then if i had room- i used to take milk powder, mac and cheese and ramen noodles. Milk powder- because sometimes milk runs out in the stores and i drink milk everyday.
I just finished my 2 years in grenada, studying for USMLE right now. If you need any further info about anything, just PM me and i'll get back to you.