It's back-to-school time, and so commences the eternal challenge: finding an easy-to-make healthy lunch kids will eat and not trade for a Lunchable.

We consulted with local nutritionists and chefs to find fresh lunch-box ideas. Their first suggestion? Involve those who eat the lunches in the packing experience.

``Have your kids be part of the process,'' says nutritionist Patricia Restrepo of Key Biscayne. ``Making fun things with them helps. Kids who have never touched a vegetable will suddenly eat them.''

Even little ones like Restrepo's 2-year-old twins help shape homemade veggie burgers.

Can't coax your kid into the kitchen?

``Have a menu meeting on weekends,'' suggests Margate-based pediatric nutritionist Lucille Beseler. Together, plan lunches for the week, then go shop for ingredients. Your child will take an interest in what he's eating and you'll have everything ready ``and be ahead of the game,'' Beseler says.

HIP & HEALTHY IDEAS

Protein sustains the body and complex carbs provide slow-burning energy to last throughout the school day and beyond. A nutritious lunch should have both, says Beseler. Try some of these combos:

• The other white meat -- For that lean protein, consider tofu. ``Kids like soy-based meat substances,'' says Katie Strong, dietician for Physicians' Committee for Responsible Medicine. ``They don't even know the difference.'' Pack a veggie burger, tofu dog or soy-based chicken tenders.

• Dip it -- ``Our kids are much more willing to eat their vegetables when there's a tasty dip,'' says Kazu Teh, owner of Lan and Yuga, and a mother of two. Hummus is always a hit. Also salsa and tahini (sesame spread). Put some in a resealable container, with a separate package of fresh bite-sized veggies like grape tomatoes, carrots sticks and celery.

• Beyond sandwiches -- Multigrain tortillas offer complex carbs and make kid-friendly wraps. Go for healthy fillings like black beans and spinach.

• Finger food -- Make bite-sized, fun-to-eat entrees ``like low-fat cheese and turkey rolled with lettuce,'' suggests chef Michelle Bernstein of Michy's and Sra. Martinez restaurants in Miami.

• Pita pizzas -- Whole-grain pita makes a kid-sized pizza. Top with tomato sauce, mozzarella and veggies.

• Thermos fillers -- Fill a wide-mouth thermos with oatmeal with cinnamon and raisins, veggie whole-wheat pasta salad, turkey or vegetarian chili, fruit salad, fruit and yogurt smoothie and soup that is veggie-rich, not cream-based. It's ``a great way to include vegetables for picky eaters,'' Teh says. Bernstein agrees and recommends ``a healthy Tuscan bean soup, low sodium minestrone or fresh tomato soup.''

• Love your leftovers -- Tonight's dinner can be tomorrow's lunch. ``I make a little extra and even box it up as I'm standing there preparing dinner,'' Teh says. ``Grilled chicken, rice, pizza, pasta, stir-fry -- it all works.''

• On the side -- Add whole-grain bread, fresh fruit or veggies to any of the above for those complex carbs and you have a nutritionally complete lunch.

• Instead of chips -- Try low-fat complex carbs like fun-to-eat edamame (soy beans in the pod) or homemade popcorn, but hold the butter. Bernstein suggests combining fruit for a treat that's both healthy and gorgeous. ``Section apples and oranges to make an `orapple.' Place the sections together, alternating one of each, and put together forming a fruit again.''

• Make your own -- Packaged trail mix can be high in sugar, fat and salt. Making your own is easy, healthier and cheaper. ``Just buy a couple of different nuts and dried fruits and toss together,'' Teh says. ``We keep a big container in the kitchen.''