A study by Hawkes Bay’s Eastern Institute of Technology on 40 schools and 2000 students has found that 90 per cent weren't eating the recommended daily intake of fruit and vegetables.
Researcher Pippa Mckelvie-Sebileau said she was surprised to see how widespread the issue is.
“It’s for children across all different types of schools, so in the low advantage schools there were almost no children getting the recommended amount of veg and in the high advantage schools there was still a really low rate, " she said.
"We were surprised to see the number of students who did say they went hungry at home and had to wait to buy more food."
The Government introduced Ka Ora, Ka Ako – Healthy School Lunches in 2019, which provides healthy lunches to over 219,000 students in 946 schools across the country.
However, nutrition and global health expert Boyd Swinburn says more should be done.
"This evidence that we've got from Hawke's Bay really feeds into that we aren’t doing enough, it's shocking and it goes nationwide... not just primary schools, primary and high schools,” Swinburn said.
“Other countries we compare ourselves with, OECD countries, our stats are shocking, they're terrible, we've got the third highest rates of obesity and the lowest mental health scores of any country.
"We should be taking these international comparisons and using that as a stimulus to improve our food systems for these kids."
She said a real change would require a shift in policy.
“Currently schools only have guidelines of what they can sell... we need stronger policy across the board to address all schools.
"For years we've been talking about it and there's been recommendations, but we need to move now, it’s urgent.
"We need serious policy we actually need to get serious about this and get serious about the kids."
The Ministry of Education said they are currently reviewing Ka Ora, Ka Ako.
The programme is slated to finish in January 2023.