A healthy lunch seems to be hard to find at school canteens.

Researchers reviewed food in more than 120 primary school tuck shops- assigning green, amber, or red ratings based on how healthy it was.

Only 19 percent scored green.

Massey University's Carol Wham says she's not surprised to see most items don't meet Ministry of Health guidelines.

"They really want at least 75 percent percent of food offerings to be in the green, which is the healthy group items without fat and sugar and salt- not highly processed."

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