One of the criticisms routinely levelled at government healthy eating guidelines is that they "don't work".
If they did, the argument goes, how come we're all fat and unhealthy?
These criticisms are often made by people in favour of revolutionary "new" health theories; the same people may also tell you that everything we've been told before about healthy eating was wrong.
Official healthy eating guidelines are notoriously slow-moving.
They typically take years to develop and update. The most recent Eating and Activity Guidelines for New Zealand Adults were released late last year; the first update since 2003.
By the time the new guidelines came out, the old ones definitely had some dust on them.
There are a few reasons for the slowness.
One is that population-based guidelines are evidence-based.
That means the team of experts who formulate them need to spend time looking at the body of evidence in each area, and at guidelines published overseas.
They can't cherry-pick individual studies, and they need to make their advice broad enough to cover a whole population of people.
Official guidelines can never take the place of individualised advice, and they're not really intended to.
The idea that our official guidelines don't work seems to me to be misguided and unfair.
And that's mostly because although we've had healthy eating guidelines for years and years, we Kiwis - contrary creatures that we are - tend not to actually follow them.
For example, top of the list in the guidelines is to: "Eat a variety of nutritious foods every day including plenty of vegetables and fruit".
We know that in real life most of us are not doing this fundamental thing. Only 41 per cent of New Zealanders eat the recommended amounts of both fruits and vegetables. This looks even worse if you consider our three veges and two fruits guideline is pretty meagre. In Australia it's five veges and two fruits.
Likewise, the recommendation to eat "grain foods, mostly wholegrain and those naturally high in fibre" emphasises heavily the benefits of whole grains.
Yet only 14 per cent of us usually eat heavy-grain bread instead of white or wholemeal bread.
This might be partly why we average well below the recommended 25-30g a day of fibre, with an average fibre intake of just 20g. The pattern is the same for salt - we eat more than is recommended, despite guidelines telling us to choose lower-salt versions - and sugar, where it's recommended we eat foods "with little or no added sugar".
Yet 30 per cent of Kiwi men and 17 per cent of women have soft drinks or energy drinks three times or more each week.
It would be fascinating to track what would happen to our collective health if, as a population, we did properly follow all the official guidelines. I bet we'd look a lot healthier than we do now.
Maybe before we adopt any radical new theories or ways of eating, we could do worse than to apply ourselves to doing better at the basics.
Niki Bezzant is editor in chief of Healthy Food Guide.