Labor Day is the unofficial end of the summer, and for many on the Island, it will be one last time to use the grill.Experts are reminding Long Islanders there are ways to enjoy a barbecue and stay healthy. They say there's no reason why grillers can't enjoy a burger or hot dog.Marlo Mittler, a registered dietician, says residents can save up to 200 calories and 12 grams of fat by using low-fat or fat-free frankfurters. For those craving a burger, she says it's a smart choice to have a veggie burger or chicken instead. Government offices across the Island are closed Monday due to Labor Day, as well as post offices, state and federal courts and banks.