EXPERT REACTION: Most new Type 2 diabetes cases attributable to 'suboptimal diet'

Seventy percent of new cases of type 2 diabetes could be attributed to a sub-optimal diet; that is a diet low in dietary fibre from wholegrains, fruit, vegetables, nuts and seed and instead- full of those white carbohydrates (refined grains, rice and potatoes), meat in all its forms, and sugary drinks. This is unlikely to be breaking news to most people. After all, nutritionists, dietitians and public health experts have arguing for decades for more attention to be given to promoting healthier diets to prevent diseases like diabetes, cardiovascular diseases and cancers. However, the extent to which poor diet is driving the global diabetes epidemic is shocking, even to me.

Supporting people to eat more health-protecting and less health-harming foods is complicated, as the article by O’Hearn and many, many colleagues demonstrates. For example in high income countries like New Zealand, wealth and education level is associated with overall healthier diets whereas in emerging economies the opposite is true. In high income countries we have seen a trend towards reducing impact of sugary drinks but increasing impact of processed meats, whereas in the lowest income regions the impact of sugary drinks has increased.

What and how we eat in Aotearoa New Zealand will have major impacts on our economy heading into the future. We face a huge burden of healthcare costs due to increasing incidence of diabetes, cancers and metabolic disorders directly attributable to unhealthy diets. Our eating guidelines pretty much say the right things and have done so for decades, with small tweaks and changes in emphasis along the way, but our diets aren’t getting any better. Why? We have relied too much on providing a little information here and there and then leaving it up to consumers to make informed choices, which, to be fair, they have done. It’s just that the evidence-based healthy eating information has been entirely swamped by conflicting messages promulgated by the food industry to eat more unhealthy foods and drinks, more often.

Our government needs to accept that we can’t have a profitable junk-food sector and a population in optimal health at the same time. It’s time to stop enabling an unhealthy food system. We need strong public policy limiting the marketing of unhealthy foods particularly to our children and healthy food policies in all public institutions (especially schools).

Eating healthily is increasingly challenging for whānau. The cost of healthy foods is spiralling. A recent survey commissioned by Health Coalition Aotearoa found that 83% of those surveyed rated the affordability of healthy food as the number one issue facing Aotearoa New Zealand. If we want people to eat healthier food, we urgently need to address the high cost of this food. The government should prioritise work on developing a package of fiscal levers to reduce the cost of healthy food. For example, this could include reductions in taxes on healthy foods subsidised by levies on sugary drinks and unhealthy foods. They should be brave with tougher regulations on the practices of our supermarket duopoly. And they need to explore mechanisms to prevent the cost of domestic food supplies being dictated by export prices.

While these things are complex and will take time, the Government could take a simple but effective action to improve diets right now. Health Coalition Aotearoa is calling on the government to expand the Ka Ora Ka Ako Healthy School Lunch programme to reach at least 50% of all school children, up from 25%. Providing children with a healthy meal every school day provides an opportunity to normalise and educate kids about healthy foods, displaces cheap, highly refined and processed foods from their lunchboxes, and provides financial relief to parents leaving more money in the weekly food budget, which could be spent on wholegrains, fruits, vegetables, nuts and seeds.

This is an interesting study, yet again confirming the link between diet and diabetes. The authors do try and look at the socioeconomic effects, but as this is by country, the averages no doubt hide the true risk and effect of socioeconomic disparity.

Overall, like the authors of the paper and the editorial, I agree we need to see more action by politicians and health officials. Hopefully, yet another paper and report will push them to take action on the availability and pricing of certain foods over others, etc. 

However, for me there is a glaring gap in the analysis and commentary. Many if not all of the regions they mention with higher rates of type 2 diabetes i.e., Colombia and Caribbean, like Aotearoa, suffer from the historical and ongoing effects of colonisation. Its effects on resources and wealth distribution, especially access to land for food security, etc. But also the loss of language and culture, and with it, traditional foods that were the opposite of what causes the issues here i.e., they were unrefined and not processed/packaged.

So any efforts to address a paper such as this needs to consider these things because the narrative can quickly turn to individuals' diet choices, but for many, those choices have been taken away. We need to ensure any discussion and action on the dietary causes of type 2 diabetes maintains a public health population focus and not an individual responsibility one.

We know that a diverse variety of wholesome foods in sensible quantities every day is the best way to lifetime health. This latest study of data from 184 countries estimates that seven out of ten new cases of type 2 diabetes can be attributed to diets that have not enough wholegrains, vegetables and too much white rice, white flour and processed meat.

Diabetes is not a silent killer, it is associated with malfunction of every organ in the body and puts a huge burden on health systems. We know that people on low incomes are more likely to suffer and die from diet-related diseases; diabetes is just one example.

In New Zealand one out of ten pregnant women has gestational diabetes which means the woman and her child are more likely to have diabetes in later life. Action today will have benefits far into the future. As Reynolds and Mann point out the food environment needs radical change and rethinking. Sustainable food based dietary guidelines need to be supported by integrated and overarching policies and practices – from the farm and sea to the fork. A whole-of-society and food system response is required as we are all responsible and everybody eats.

New Zealand’s food exports are largely red meat and butter and paradoxically we import huge quantities of white rice, white flour and sugar…cheaper 'food' but in the long run taking years from life and life from years.

Designed for profit not health, our current food systems are inundated with ultra-processed, low in nutritional value, well-marketed and appealing products.

O’Hearn et al.’s global study provides robust evidence on how our long-term health is suffering as a result of this. In their editorial, Reynolds and Mann highlight the way food systems are influenced by government policy and the potential for good policy to have a health-protecting effect.

The school food system in Aotearoa New Zealand is a great example of how children can be protected from immediate and long-term harm through better nutrition. Since 2020 around 200,000 students in 1000 schools receive a free and healthy school lunch through the Ka Ora, Ka Ako programme. Positive effects on food security, student wellbeing and family financial hardship have been demonstrated.

However, there are still many kids missing out as they attend schools that are ineligible for the programme, and generally, their diets are poor. Our research has shown around 90% of students in Hawke's Bay were not eating enough vegetables to have a health-promoting and -protecting effect.

School food environments have the potential to equitably reverse this trend. Based on feedback last year from parents, teachers and public health physicians, the government has committed to considering whether only healthy drinks should be sold in both primary and secondary schools, and whether guidelines should also apply to food. This is a step in the right direction but with the outcome not announced until the end of the year we need faster action to ensure children’s rights are maintained to have their long-term wellbeing protected, especially in light of O'Hearn et al.'s findings.

With the cost of living crisis and rising food costs due to failing global food systems, we urgently need a national food security and sovereignty plan and to allow more children to benefit from good food that protects long-term health outcomes through the extension of the Ka Ora, Ka Ako programme to more schools.

As a public health dietitian, I have some specific recommendations for the New Zealand Government to help curb the trend of Type 2 diabetes, particularly the suboptimal diet of insufficient whole grains, excess refined rice and wheat, and excess processed meat.

The New Zealand government could develop and implement a national healthy eating strategy with health professionals, food industry stakeholders and community organisations. This comprehensive strategy needs to include policies that promote access to healthy foods and reduce the availability of unhealthy foods.

The government could also consider implementing a tax on sugar-sweetened beverages, which have been linked to an increased risk of Type 2 diabetes. The revenue generated could be used to fund diabetes prevention and management programs.

Additional funding could be allocated to support community-based nutrition education programs that provide practical advice on how to adopt healthier eating habits. Also funding for programs that support low-income families to access healthy foods, such as subsidies for fresh fruits and vegetables and increased funding for food banks could also be an effective strategy.

Government action needs to take a multi-faceted approach that combines policy changes, education programs, and support for individuals with diabetes.