Ian McLean Green candidate for Tauranga

I once spent some time in Mozambique, in southern Africa, and noticed immediately that obesity was not a problem for those people. They were recovering from a civil war and the standard of living was low, but they were generally well-fed without being overweight.

The local policeman was memorable. He was the only obese person I saw in my time there.

It used to be that well-off people were fat, and poor people were not. When drought or crop failure occurred, it was the poor people who suffered most because they worked hard and had few reserves. Being overweight projected power and wealth, as was the case with that policeman.

Today, in developed nations, the reverse is true. We have an epidemic of obesity, but the people who suffer from it most are not those who control the resources in our society. Nor is it the 'beautiful people” – those who grace the pages of the women's magazines. In our resource-rich consumer society, we value health and vitality far more than displays of wealth, and being slim and well-groomed are key criteria.

So why are poor people fat? Most analyses of this issue focus on how individuals need to change their behaviour – eat less, exercise more, avoid takeaway foods of high fat content and dubious nutritional quality. Government is investing $65 million in those issues in schools this year.

But the issue can also be addressed at a society level. A key cause of obesity is income inequality – the income difference between the richest and poorest people in a society. Wilkinson and Pickett, in The Spirit Level (Penguin), lay the results out for all developed countries of the world and their conclusions are unarguable.

Poor people in the developed nations are highly stressed, with consequences such as anxiety, depression, drug abuse, violence, alcohol addiction, smoking, and most relevant here, obesity.

Countries with the lowest income inequality also have the lowest levels of these problems. As a result, they have low costs for healthcare, the legal and prison systems, and personal security. Few children live in poverty, domestic violence is infrequent, and education success is high.

There are many ways to reduce income inequality, but high minimum wages and a tiered tax system are key elements. The benefits accrue to both rich and poor people. E.g. if we all have about the same stuff, there is no need to steal from each other. Aotearoa should learn the lessons of The Spirit Level and begin treating the causes, and not the symptoms, of our current malaise.