This week, science reporter Jamie Morton talks to some of our best scientists about the cutting-edge research they are leading.
Today: Tackling the bulge to improve NZ's nutrition

Part 1 of a 6-part series

The figures are as compelling as they are frightening. According to a recent Ministry of Health report, poor nutrition and obesity combined account for 11 per cent of health loss - death and disability - in New Zealand.

That is even greater than the loss attributable to tobacco.

Based on present rates of increase, obesity is predicted to overtake smoking as the leading risk factor for disease by 2016.

We're not alone: most high-income countries are grappling with the impact of poor diets and obesity.


Diets in these countries are generally too high in salt and saturated fat, and fruit and vegetable intakes are too low, but it's in obesity rates that New Zealand stands out.

Our rate has more than doubled in the past 20 years and at present stands at 31 per cent of adults and 11 per cent of children. In OECD rankings, New Zealand is the third-fattest country.

What can be done to reverse the worrying trend?

A major five-year, $5 million collaborative study funded by the Health Research Council is exploring the root causes of the growing problem and identifying simple solutions to help curb it.

The study team includes world-renowned researchers from the University of Auckland, University of Otago Wellington, the George Institute of Global Health in Sydney, and the Oxford University.

A recent obesity series by international medical journal the Lancet highlighted nutrition labelling, pricing, marketing and reformulation of foods to reduce sugar, salt and saturated fat as cost-effective measures.

"However, robust evidence on the impact of these interventions on New Zealand population diets and health is lacking and, as such, the likelihood of their implementation is impeded," said the programme's leader, Professor Cliona Ni Mhurchu, from the National Institute for Health Innovation at the Auckland University's population studies school.

"Our team has been at the forefront of these research areas over the past decade and our combined expertise means we are uniquely placed to investigate and quantify their impact on nutrition."

Professor Ni Mhurchu said there was good evidence most people didn't understand nutrition labels and many countries, including New Zealand, were proposing to implement simple, interpretive front-of-pack labelling to help consumers make healthier food choices.

But there is still no evidence regarding the impact of that change on the foods people buy.

The researchers will use a unique smartphone application to enable study participants - 1,500 Kiwi household shoppers - to scan barcodes of food packages with their phone camera and receive an instant front-of-pack label.

The study will test two types of labels - traffic light labels being used in the UK, and the Health Star Rating System recommended for introduction in Australia.

Their effects on purchasing behaviour will be compared with that of the standard nutrition information panel commonly found on the back of food packages.

Food prices, a key determinant of food purchases, will also be analysed.

Professor Ni Mhurchu said health-related food taxes and subsidies, such as soda and fat taxes and subsidised fruit and vegetables, were being increasingly proposed as ways to promote healthier diets.

Before New Zealand followed the lead of other countries, policy-makers needed to know if such measures were likely to save lives and money. "However, our New Zealand food price elasticity data, essential for such calculations, are very poor," she said.

Researchers will use a New Zealand Virtual Supermarket - 3D software that simulates a real supermarket - as a setting in which to randomise participants to changes in food price and then see what impact price changes have on purchases of taxed or discounted food items.

"This research will generate precise and policy-relevant food price elasticity values that can be used to estimate the health gains associated with food taxes and subsidies."

Another project will look at potential changes to the composition of foods to reduce salt and saturated fat, and gauge our everyday exposure.

To do this, researchers will marry Auckland University's Nutri-track database with food purchase data from Nielsen consumer panels to create a sales-weighted estimate of our exposure to salt and saturated fat in the food supply, and how it's changing over time.

The daily exposure of children to unhealthy food is just as crucial a question - and one that will be answered with one of the programme's most innovative studies.

"International research has shown that food marketing influences the preferences, purchasing behaviour and diets of children," she said. "However, little is known about [Kiwi] children's exposure to non-TV food advertising and there has been no quantification of their exposure to the full range of marketing media."

The approach: fit 224 children with automated smartphone cameras to passively record their everyday food environment, along with how many times, and for how long, they encounter food marketing.

"This will enable us to identify opportunities to limit children's exposure to junk-food marketing."

The fifth major project will estimate the effects of nutritional policy options, such as better labelling, taxes and subsidies, on long-term health and inequalities in New Zealand.

The researchers will pull together data from the rest of the programme and combine them with the best international evidence to model various nutrition interventions.

"What makes this programme different from a lot of other research is its focus on translation into action," Professor Ni Mhurchu said.

"Our research is designed to answer policy-relevant questions and effective interventions identified could be readily translated into policy."

FoodSwitch is a smartphone app that you can download for free. Photo / Chris Gorman
FoodSwitch is a smartphone app that you can download for free. Photo / Chris Gorman

Eating right

University of Auckland researchers Dr Helen Eyles and Rebecca McLean list 10 easy ways to improve diet.

1. Choose whole foods over processed foods: Whole foods include fresh and frozen fruit and vegetables, nuts, lean meat, poultry and fish, and plain dairy products. Whole foods are usually found around the perimeter of the supermarket. Processed foods are usually found in packages in the middle aisles of the supermarket.

2. Eat breakfast: It's important to start the day with a nutritious breakfast. Choose foods such as wholegrain breads, high-fibre breakfast cereals, vegetables, fruit, eggs and low-fat milk and dairy foods.

3. Drink plenty of fluids each day: Drink water throughout the day and limit sugar-sweetened drinks and alcohol.

4. Have fruits and/or vegetables at every meal and for most snacks: Fruits and vegetables are high in fibre, vitamins and minerals. Aim for at least half a plate of vegetables at lunch and dinner.

5. Avoid deep-fried foods, dairy fat and meat fat: Foods high in meat and dairy fat are bad for your heart and your health. Trim fat and skin off meat, and avoid deep fried foods, chips, pies, pastries, butter and cream.

6. Select wholegrain breads and cereals: Replace white bread and low-fibre breakfast cereals with wholegrain and high-fibre breads.

7. Check the ingredient list on packaged foods: Foods with a smaller number of ingredients are usually less processed and therefore healthier.

8. When buying packaged foods try to choose varieties low in sugar: Check the nutrition information panel on the back of food packages - use the 100g column to compare products, and the "per serve" column to work out how much sugar a single serve contains. Aim for products with less than 10g of sugar per 100g, and have no more than 50g of sugar in total for the day.

9. Use FoodSwitch to make healthy choices easy: FoodSwitch is a smartphone app that you can download free on the Apple iTunes or Google Play store. Scan the barcode of any packaged food using your phone camera and receive a simple traffic light nutrition label. You also get suggestions for healthier options.

10. Look online for free healthy recipes: The Heart Foundation has lots of recipes to download free on its website, including a great new recipe book, Cheap Eats. There are also tons of healthy, free recipes on the Healthy Food Guide website and you can join its mailing list to receive new dinner ideas straight to your inbox.

The series

Part 1 (today): Tackling the obesity epidemic
Part 2: Solving the human jigsaw puzzle
Part 3: The Kiwi-made biotech wonder
Part 4: Learning mental time travel
Part 5: The birth of the artificial muscle
Part 6: The age of wearable computing