We own at the Marriott next door, and go for 2 weeks every other year. I've pretty much got our packing down after so many trips!
I bring a suitcase with nonstick Reynolds Wrap, lots of ziploc bags, several plastic food storage containers (for our own leftovers), a bottle of Spike (it's a great all purpose season salt blend, excellent on pretty much everything), other spices, Splenda, a can of Pam, several small bottles of condiments like a tiny pancake syrup & mayo as we may only need a small amount, package of pancake mix, etc. Also maybe a taco dinner kit (or buy that at Target). I may bring a few side dish things too like rice mixes. Oh, and we like Korean rice so will either brings a small bag or buy it at Target. Then we do a big stock up trip to Costco for fresh fruit and a veggie tray, salads, and of course wine and booze (their brand of French vodka is actually Grey Goose and it costs about what you'd pay for two cocktails at the bar!). I'll also buy a package of frozen burgers and buns (the burgers can be thawed and used as ground beef, so we'll make tacos once and burgers a couple of times). We drink soy milk, and like Costco's brand so will also get a case of that as well as a couple cases of bottled water. Then we use Target or
Walmart for smaller amounts of things.
We tend to eat lunch out if we're running around, but if we're in the villa we'll make sandwiches and salads, or I'll cook a nice lunch. You can get frozen chicken terriyaki at Costco, which is great with Korean rice (the Marriott villas all have rice cookers now) and dried seaweed (Target sells it there; Costco does too but it's a huge pack). Add some nice fruit (Costco has Hawaiian pineapples, yum, and they're so cheap) and you've got a great lunch. If we're in the villa we'll do that and then have down time to stay out of the sun for a couple hours.
We'll grill fish sometimes, and Costco tends to have very fresh fish! Just bring seasoning from home and a small bottle of good olive oil or buy that at Target. Costco often also has nice sashimi trays too!
We'll buy breakfast things at Target, like eggs, sausage, biscuits (my kids like those refrigerated ones), frozen hash browns maybe too. I'm not a big breakfast eater, but the kids like it! I also tend to bring a couple packs of McCormick instant sausage flavor gravy mix: just add 2 cups water and you've got decent gravy for biscuits.
I bring a small cooler, so we bring snacks, sandwiches, and drinks to the pool.
I'd love to keep this place to myself, but what the heck! There's a newer place by Safeway in Kapolei called Sushi Bay - it's a conveyor belt sushi place. They have the best sushi and great prices - we used to love Genki Sushi for years but now prefer this place!
We don't spend more eating in Hawaii than we do at home really, but we lived there for 3 years so know what we like and tend to spend a lot of time at the resort now.