Fast foods are being served up in ever bigger portions and that means there's more salt in them, a University of Auckland study has found.
Pizzas in particular are being served up in larger portions, the study found. Photo: 123RF
Researchers included almost 5500 fast food products in 10 major fast food chains.
The study, published in the Nutrition Journal, used publicly available data from the companies' own websites and through visits to the restaurant branches for any material not found online.
It found the size of fast food servings, and their energy density, had increased significantly between 2012 and 2016.
Less salt in new and reformulated products was offset by the fact that overall the portions were bigger.
Read the full study here.
Pizzas had a large increases in serve size and were "one to watch", study leader Dr Helen Eyles said. There were also "undesirable changes" in three other groups; desserts, salads and sandwiches.
Dr Eyles said New Zealanders were consuming more fast food and researchers were keen to track whether it was becoming more or less unhealthy.
"We found a five percent increase in serve size over that five-year period.
"It means that people are consuming more energy when they have a fast-food meal but it also means that per serve it's increasing things like the content of sodium and sugar as well."
Dr Eyles said fast food companies and the government should be doing more to inform New Zealanders about what and how we're eating.
"We'd really like some government-led targets for fast-food manufacturers to work towards - some standard serving sizes and sodium content for example," she said.
"Government should really take a lead in those targets and work with the food industry as well" - Dr Helen Eyles
"It would also be great to see fast-food manufacturers includong nutritional information, serve size, in the public domain."
Dr Eyles said an important consideration is the impact on young people, the highest consumers of fast foods. National Nutrition Survey data found 38 percent of 15-18 year olds and 42 percent of 18-30 year olds had consumed fast food in the past month.