The Government is expected to announce a lunch in schools programme today.

Newstalk ZB understands Prime Minister Jacinda Ardern will reveal a 30-school trial for free school lunches, at a cost of $45 million.

AUT dietitian Caryn Zinn told Mike Hosking she is excited and nervous about it at the same time.

She says centralising school lunches and putting guidelines around it would be very beneficial, as long as it's done properly.

Zinn says school lunch boxes are generally full of packets and ultra-processed foods and are absolutely devoid of protein.

"If you look at school lunches at the moment, they are full of packaged and processed foods."

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