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The latest University of Otago department of human nutrition annual food-costs survey reveals it costs $78 to feed a teenage boy a basic diet for one week, and $65 for a teenage girl.
This increases to $122 and $101, respectively, for a liberal diet with more expensive cuts of meat and convenience and imported foods.
This compares with $62 for a man and $58 for a woman on a basic diet and $97 and $91 on a liberal diet.
The increasing cost of food is well known to Latham and Nicola Wardhaugh, whose three teenage sons cost more than $100 each a week to feed.
Middle son Benjamin swims four mornings a week, and bikes and runs three or four times a week.
To fuel his exercise, not to mention his growing, he eats each day, on average, four Weet-Bix before training, followed by fruit and toasted muffins. Lunch usually consists of about four buns, fruit, yoghurt and a muffin.
Afternoon tea could be leftovers or toasted sandwiches, followed by a dinner of meat and vegetables, dessert, and a supper of four pieces of toast or porridge.
"That's just the way it is with growing boys [and] the fact they are all into their sport," Mrs Wardhaugh said.
The family go through 20 litres of milk a week and "have not got a big enough car" to survive on a weekly shop, so visit the supermarket during the week, Mr Wardhaugh said.
"You notice the difference when someone is away."
The annual food survey was conducted by student dietitians who collected data from four different supermarkets in New Zealand's five main centres.
They took the shelf price for the lowest-priced product, averaged the cost out across the stores, and created diets based on New Zealand Food and Nutrition Guidelines.
Associate Prof Winsome Parnell said there was "nothing unexpected" in the results, as the ever increasing cost of food was well known.
As for the cost of feeding teens, she said it came down to "sheer quantity ... as they eat more".
"Mothers of teenagers will tell you they have ways to fill them up."
She also understood people often struggled when the cost of living increased and that many "made accommodations in the food line" to pay fuel bills.
However, spending less on basic food items increased the risk of not getting necessary nutrients.
"There was huge alarm in the media about the price of tomatoes, lettuce and peppers ... but you don't have to eat those out of season - there is no nutritional disadvantage. I'd say have soups rather than salads."