Making kids swap soda for water is a challenge - Eliza McCartney

A Kiwi Olympic bronze medallist is challenging New Zealanders to curb their fizzy drink habits, but says convincing kids can be difficult.

Pole vaulter Eliza McCartney is the new face of the Switch to Water Challenge which encourages people to swap sugary drinks for water for 30 days.

McCartney won bronze in pole vault at the 2016 Rio Olympic Games at just 19 years old, and says after stopping drinking soda herself "ages ago" she can feel the difference.

"You just stop wanting them and it just feels better."

Dental treatments were the second biggest cause of hospital admissions for children last year and more than 6600 children under the age of 12 have ended up in hospital with a rotten tooth.

McCartney says fizzy drinks bring on a variety of problems.

"You've got the sugar content, which is the obvious one, you've got calories which you don't need, not getting nutritional value and then on top of that you've got the acidity which eats away at the enamel of teeth. It's just all sorts of issues."

However, she says kids can take a while to come around to the idea.

"You get the people who drink them every day, all the time. So I think it's about taking the steps and getting yourself into it."

Diet isn't the only change in McCartney's life since finding sporting fame. Now, she also copes with public and media attention.

"People recognise you and it is quite a difference. I don't notice it so much anymore but my family notice that people do tend to look at you a little bit more.

"So that's really changed, but other than that you just kind of adjust.

McCartney is currently preparing for summer pole vault season, including the Commonwealth Games on the Gold Coast next year.

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