Lower sodium concentration offset by bigger portion: Reformulation woes in New Zealand fast food chains

By Tingmin Koe

- Last updated on GMT

In New Zealand's fast food chains, a lower sodium concentration in food is offset by a bigger serving size. ©Getty Images
In New Zealand's fast food chains, a lower sodium concentration in food is offset by a bigger serving size. ©Getty Images

Related tags Fast food Sodium Portion size

The sodium density of fast food in New Zealand has dropped by 7%, but the overall increase in serving size has resulted in higher energy and sodium intake, a group of researchers found.

The researchers conducted a study on 5,468 fast foods selling at New Zealand between the years 2012 to 2016. Burgers, pizza, sandwiches and dessert were some of the foods studied.

These foods came from 10 major fast food chains, including Domino’s, Hell Pizza, Pizza Hut and Subway.

Researchers found that there is a visible drop in sodium density in the fast food studied, as a “moderate and significant reduction over time” ​was observed. The reduction in sodium density ranged from -35.7mg/100g to -7.9mg/100g, with a mean of -21.8mg/100g, which is equivalent to a 7% reduction.

One of the largest absolute reduction in sodium density was seen in burgers, with reduction ranging from − 74.2mg/100g to − 45.1mg/100 g.

Chain store wise, Burger King and Hell Pizza contributed most to the sodium density reduction, with reduced sodium density in the range of − 70.3mg/100g to − 44.8mg/100g and − 72.1 mg/100 g to − 20.31mg/100 g respectively.

A drop in sodium density is however offset by a bigger serving size, resulting in overall increases in energy and sodium levels.

“These reductions (in sodium density) per 100 g did not translate to a drop in sodium per serve, due to the increase in serve size,”​ researchers said.

This is an important finding given larger serve sizes for products such as beverages and desserts would result in an increase in total sugar per serve, and for chains such as Domino’s, Hell Pizza, and Pizza Hut, higher saturated fat per serve.

Bigger serving size

The serving size of chicken, desserts and pizza from fast food chains grew the most, increasing by 70%, 36%, and 25% respectively.

The increase was most noticeable in Pizza Hut, Hell Pizza and Domino’s, growing by 44%, 34%, and 10%.

The overall increase in serve size was a factor in increasing energy and sodium per serve, the researchers observed.

“The overall increase in serve size, rather than large increases in energy and sodium concentration per se, has resulted in an overall increases in energy and sodium per serve”,​ the researchers said.

In conclusion, researchers said that “New Zealand fast foods have become larger and more energy dense over the past five years. Lower sodium concentration in new and reformulated products has been offset by overall increases in serve size.”​ 


In New Zealand, food away from home contributed 25% to household food expenditure in 2016. 

To improve the public’s dietary intake, the New Zealand government led a voluntary front-of-pack labelling system for packaged foods. Food companies can also make voluntary pledges to improve their products and reduce obesity rates for children.

We also recently reported​ that the nation’s drinks sector is open to follow Australia beverage industry commitment in introducing a sugar reduction in beverages.

Source: Nutrition Journal 2018

DOI: https://doi.org/10.1186/s12937-018-0373-7

“Five year trends in the serve size, energy, and sodium contents of New Zealand fast foods: 2012 to 2016”

Authors: Helen Eyles, et al

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