Parents know the drill: pack something nutritious, using each of the four food groups, into your children's lunch boxes. Include a chunk of cheese, because this protects teeth. Include a treat because you're a softy (those giant bags of chocolate bars on special offer last month come in handy). Hope they'll eat the good stuff first.
Collect children from school. Peak inside lunch box. The uneaten cheese sandwich lies abandoned in a pool of juice from the half-empty carton. The apple has a bite out of it, if you're lucky. The cheese has apparently been used as a rubber. The chocolate bar, the crisps, the biscuits? Gone.
No wonder more and more schools are trying to combat the trend. In Kilkenny and Waterford, the idea has taken off with the South Eastern Health Board's Healthy Lunch Project. Out of 100 schools, only one has rejected the notion because "schools have no right to tell parents what to feed their children".
Of course they have the right, says Susan Higgins, the nutritionist who runs the project. "A school can say: 'you must wear a particular uniform if you attend our school.' So why can't they say: 'if you attend our school, you must bring a healthy lunch'?"
In some schools, it's a step forward to have just one "healthy lunch" day a week, when biscuits, chocolate, fizzy drinks and crisps are banned. Other schools limit treats to one day a week. Still others ban nothing, but insist each child bring some fruit.
At my daughters' school this year, all treats that manage to sneak into lunch boxes will be taken away from Monday to Thursday, replaced with fruit and handed back at the end of the day.
Good nutrition is essential to school performance, but there are many other cultural messages keeping our children from eating properly. The Slβn nutrition survey found the bulk of nine- and ten-year-olds eat lots of sweet foods. Yet a frightening proportion of them, especially the girls, were trying to lose weight.
The cultural double messages that surround food are as confusing for children as they are for adults. Food is fun - sweet, chewy, chocolatey, creamy - but it is also bad for you, making you fat.
The battle of fun versus nutrition is nowhere more apparent than in the school lunch box. Leβn O'Flaherty of the National Dairy Council says: "Our experience tells us that many, many parents have anxieties that their children are not getting adequate nutrition from the food in the lunch box. From the teachers' point of view, many observe that too many children are eating nothing but crisps, chocolate, snacks and confectionery for lunch."
Variety and novelty are the keys to preparing a packed lunch that children will eat, she says. Vary the bread, for example, using pitta, bagels, rolls, wholemeal baps or tortilla wraps. Also, change the fillings - ham, cheese, tuna, salad, egg - from day to day. Instead of sending biscuits to school with your children, try baking cheese straws, which keep for weeks.
Grate three ounces of cheese into a bowl with two ounces of plain flour and a teaspoon of baking powder. Rub in two ounces of butter and add an egg yolk to make dough. Flatten the dough on a board and cut into straws. Cook on an ungreased baking tray for 10 minutes at 220 degrees.
There are plenty of other good ideas in The Lunchbox Book (Hamlyn, £6.99 in UK), by Penny Stanway, a doctor and author of Breast Is Best, and Sara Lewis, food editor of Practical Parenting magazine.
The problem is, some of them take between 30 minutes and an hour to prepare. Imagine going to all that trouble, then having the product return home, soggy, in the bottom of the lunch bag.
The day my kids start eating aubergine and feta rolls, red-lentil and rice salad, spinach ricotta puffs or beetroot and cream-cheese sandwiches - with horseradish - is the day I eat their left-over soggy cheese sandwiches for my tea.
For a free copy of Healthy Eats For Midday Feasts, write your name and address on a postcard marked "Lunches" and send it to National Dairy Council, 28 Westland Square, Dublin 2