The key is looking beyond just sandwiches, says Tracy Griffith, author of a new book called Stealth Health Lunches Kids Love, to be released here next month. Griffith, who counts a sushi mat as a lunchtime essential, has declared war on the usual suspects, from packaged crisps to sugar-loaded snacks. She's armed with gluten-free tacos, wraps, onigiri-style rice and sushi.
Some of the recipes don't sound too friendly - Green Slime, Schmoo, or Alligator Scales, anyone? These are actually the book's more stealthy inclusions - nifty ways to tuck veggies into a lunch so they are almost unnoticed.
Green Slime is a spread made of avocado, sour cream, chopped basil and spinach that can replace mayonnaise or as a healthy dip with crisps - preferably home-made from kale (the Alligator Scales), or sweet potato.
Dips, spreads and sauces are an effective way to subtly introduce children to a wider range of healthier flavours, says Griffith.
"They are basically purées," she says. "And it's in the nature of a purée to cram goodness into one super concentrated burst."
Schmoo, her pesto cream cheese recipe, includes half a cup (30 grams) of parsley - rich in vitamins A, C, and K.
"It's hard to imagine anyone eating that much raw parsley, but mixed with the other ingredients kids just love it," she says.
Not all of the options are so underhandedly healthy, but many could become lunchbox staples. Quarters of cucumber show up in a Cucumber Boats recipe, stuffed with sushi rice and home-made sesame sauce, and are robust enough to rattle around a lunchbox until required.
Crunchy pebbles are baked chickpeas drizzled with olive oil, and dusted in sea salt and paprika - little nibbles just begging to replace crisps. Pizza-tillas use Griffith's gluten-free tortilla recipe, and are rolled with cheese, shredded chicken, spinach, home-made tomato sauce and a red pepper spread.
As youngsters, the Griffith clan, including Tracy's half sister actress Melanie, grew up reading Bon Appetit magazine instead of Judy Blume and watching cooking shows rather than cartoons. "We were foodies before the term was even invented," says Griffith.
The foodie tradition continues - Griffith's six-year-old nephew Stone seems to be following in the same footsteps, enjoying acting as his aunt's sous chef. But Griffith realises many children are not as enthusiastic about the range of foods her nephew munches, and she wants to change that.
Dishes for the book were road tested by Hong Kong children of pre-school age and up. Many donated wacky name suggestions along with their food reviews. (Not Green Slime - that dubious credit goes to her husband.)
With child obesity rising in Hong Kong, more schools are promoting healthy eating policies.
Some parents say the move encourages a level playing field for healthy lunches, and stops children vying for chocolate, crisps or sweets their friends might have brought in.
But others say that prepping healthy food is time-intensive and lunch often gets brought home untouched.
A little bit of stealth can go a long way. "Healthifying" a lunch should be done in baby steps, says nutritionist Karin Reiter, founder of health consultancy Nutritious and Delicious, who runs workshops for parents.
"Don't be too drastic. If you change the whole nature of a child's lunch, they get alarmed," she says. For example, first try adding some sliced onion or chopped herbs to a tuna and mayonnaise sandwich. Later, mayonnaise - commercial versions can be high in salt and saturated fat - could be replaced with Greek yogurt. As a last move, change nutritionally poor white bread for a whole grain roll, which is healthier and less likely to go soggy by lunchtime.
Complex carbohydrates found in grains are energy givers that keep concentration levels high, and help children power through the school day, so it is vital to include them.
Whole grains have higher levels of essential fatty acids, zinc and vitamin K than their refined, and starchier, white versions. The fibre and protein from whole grains also offer a more stable and longer lasting energy supply. Only the words "whole grain," on packages guarantee the real deal - as opposed to brown, wheat or rye.
Boxes packed with bagels, pita bread, crackers, tortillas and bread rolls ensure variety, but children can still reject these if they have disintegrated by the time lunch comes around. Separating the ingredients eases this issue. Crackers with separate cheeses, tortillas that children construct themselves, and pita paired with hummus or bean dips are healthy and durable.
Pasta, quinoa, bulgur, cous cous, rice and noodles served as cold salads - dotted with specks of healthy half-hidden vegetables, fruits and protein such as shredded chicken or egg - are also more likely to remain tempting to eat by lunch time.
Good lunches are packed to a 3:2:1 ratio, says Sally Poon, a registered dietitian, whose advice echoes government thinking.
A healthy lunch should provide one third of the energy, protein, fat, dietary fibre, vitamins and minerals a student needs every day. Imagining a lunchbox divided into six sections helps parents to pack the right nutrients.
Three of those sections should provide energy via grains or cereals, two should be fruits and vegetables and one protein. "Try to include some dairy products in your lunchbox too," says Poon. "It's important to keep teeth healthy and bones strong."
Offering a variety of different healthy options is more pleasing to a child than one or two.
Lisa Fossey is owner of The Nutrition Clinic, and runs workshops on lunchbox prep for domestic helpers. She advises cutting fruit into bite-sized segments, and providing a rainbow of colours.
"When foods are colourful they look more appealing. Including lots of colours means you also offer a wider spectrum of nutrients," she says.
Sugar-laden snacks can cause sharp energy spikes and can reduce focus, but not all treats are forbidden. Home-made cakes and muffins can be sweetened naturally with fruit sauces, such as apple or banana, and upped in nutritional value with squash, beets or courgette. Add seeds to a cake mix to boost omega three fatty acids for good brain development - chia, flax or poppy seeds are also good, says Fossey. The Stealth Health cookbook has a recipe for chocolate bars made with raw chocolate, which is low in sugar but high in antioxidants. Manufactured muesli or granola bars can be high in sugar. Make home-made mixes of roasted oats, cranberries, seeds, and nuts if the school allows them.
When looking at food packages check sugar content - five grams is about equal to one teaspoon. Fizzy drinks are famously high in sugar, but so are most juices. "I always advise water," says Fossey, adding that it can be flavoured with lime or lemon, cucumber, orange or strawberries.
If home-made tomato sauces, bean dips, herb spreads, and cakes sound time intensive, that's because they can be. "It's part and parcel of eating well, unfortunately," says Fossey. "The frozen meals and convenience foods that sprung up when I was young answered a call for fast food and quick meals but they have been found not to be good for us."
Send children to school with dinner leftovers, she advises. A wide-neck thermos can be used for hot meals, school rules permitting.
Mother of three Niamh Armitage became better acquainted with kitchen prep when her eldest daughter started school and she couldn't face the thought of sending her off with yet another cheese sandwich.
Her girls now help devise monthly lunch plans. "If we have a meal out they like, I suggest it as a lunch idea," she says. Involving them means more health, less waste. Each is allowed two "won't touch," ingredients at anyone time.
A recent rotation included a broccoli, red pepper and goat cheese frittata, chicken noodle salad, vegetable soup and a quinoa salad.
Parents who think their own children wouldn't eat these things are missing the point.
"You really have to work out what it is your kids will eat. You might be surprised at the amount of different things they are eating over a month," she says.