Targeted at 11 to 14 year olds, the £120,000-plus "Cool School Fuel" campaign will feature a combination of full-page colour advertisements in monthly and weekly magazines as well as an online presence.
Magazine titles will include Top of the Pops, Bliss and Match and the launch of the marketing push will coincide with next week's National School Meals Week, running through to March 2008.
LACA national chairman Sandra Russell said: "The changes taking place within school food has come as something of a culture shock to a number of secondary school students and many have voted with their feet."
Russell said the move to change young people's diets would be a long-term one that needed to be communicated relevantly.
LACA's own research published in July found school meal uptake in secondary schools had bombed and was now just 35% compared with 42% in 2003/04.
This is thought to be the lowest level since the creation of the school meals system in 1944 and last week education standards watchdog Ofsted added to the woe by revealing three-quarters of schools inspected since junk food was restricted in 2006 have seen meals uptake fall.
By Chris Druce
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