Energy drinks have been banned from Greymouth High amid growing concern over the number of girls skipping meals.
Health officials say many students have been substituting a proper breakfast with energy drinks, or not having breakfast at all.
A meeting will be held next week to discuss solutions.
The school has decided to ban energy drinks from the beginning of term two, starting on April 23. Students caught with them will have them confiscated.
Another school in the town, John Paul II High, has not banned the drinks, but says it does not sell them at the canteen or promote their consumption.
A number of primary schools in the area already ban energy drinks.
Community and Public Health nutrition promoter Jennifer Brand said it was a real concern so many children and teenagers skip breakfast.
"Without a good breakfast it makes it really difficult to meet the daily requirements of a number of nutrients.
"Not only that, those who eat breakfast learn better as they have better energy levels and concentration, they are more active and have a healthy weight. It also sets them up with healthy habits so they become healthy adults," she said.
Healthy schools co-ordinator Kathryn Cannan said she had questions about the root cause of the problem, which needed to be answered before a decision was made on how to combat it.
Ms Brand said some of the most nutritious breakfast options were the most affordable, such as wheat biscuits and rolled oats. Those who found it hard to stomach food in the morning could try a smoothie or a banana wrapped in a piece of wholegrain bread.
The average serving of energy drink V has seven teaspoons of sugar, according to Community and Public Health figures.
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