The expansion of New Zealand waistlines

With the release of the 2008/09 nutrition survey summary report last week, I was heartened to read that diet-wise, New Zealand adults seem to be starting to make the right choices.  According to the survey, since 1997 we’ve reduced our overall energy fat, saturated fat and sugar intakes.  We’re eating more healthy fats and protein, fruit and selenium.  We also have lower total cholesterol levels with a better total:HDL-cholesterol ratio, potentially due to these dietary changes, but more likely due to higher rates of statin use.  A couple of interesting findings were the drop in our intakes of vitamin A, iron and zinc; possibly resulting from cutting down on full cream dairy products and red meat.

But the real kicker is what’s happened to our waistlines, despite all this apparent healthy change.  There’s no doubt about it – we’re all getting fatter.  Sadly, as is often the case, this trend disproportionately affects certain groups in the population, with obesity rates amongst Maori and Pacific peoples in particular, starting to scale to dizzying proportions.

While everyone agrees the reasons are multifaceted, a number of experts have provided commentary in the past week as to why this dichotomy is being seen, including (and I’m paraphrasing for the sake of brevity):

1. “It’s because people under-report what they eat in surveys” (Rod Jackson)

Yes, this has been documented in the literature, but in comparing like methodology with like methodology are we really likely to be recording our food intake any less accurately now than we were in 1997?  Even with an interviewer in our homes and going through our cupboards?  I’m not sure this is the only explanation.

2. It’s partly because we’re less active than ever before and the survey did not assess activity levels.

Certainly the basic energy in: energy out equation loop isn’t completed without an assessment of physical activity levels.  There is no question that sedentary behaviour is the elephant in the room with respect to obesity.  No matter how much we idolise our sporting heroes as a nation, the majority of us are more likely to sit on our backsides for most of the day.  Every day.  But, are we likely to be even more sedentary now than we were in 1997?  The 2006/07 NZ Health Survey found no change in regular physical activity between 2002/03 and 2006/07.  However, according to Professor Grant Schofield, our levels of sedentary behaviour are likely to be on the increase, with more hours of TV viewing, more sedentary jobs and greater car ownership/distance travelled by car in the last 15 years.  I don’t think we’ve heard the last on just how dangerous sitting can be for our health.

3. “It’s because our environment is too jammed with easily available high fat, salt and sugar foods” Robyn Toomath.

This is where we start to go around in circles, because the dietary intake data on the whole indicate we’re actually eating less fat and sugar.  In fact the only source of sugar which is growing in our diets seems to be fruit.  And in our fear of fat we seem to be switching to low fat dairy at the expense of retinol intakes and cutting out red meat to the expense of our zinc and iron intakes.  So are we reporting our intakes correctly? (… and the circular nature of this dicussion goes on).

I would love to know what you make of all of this.  It would be great to get a discussion going.  Just insert a comment below (if there are no comments yet you need to click on the no comments box in order to make one).



Categories: Food and Nutrition Events, Food Trends, Health Promotion, Nutrition and Health, Scientific Research

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4 replies »

  1. Is it possible 12 years later to say the survey is comparing like with like? Since 1997 there has been a lot of very public discussion around what constitutes healthy eating. I suspect many people would be able to tell you exactly what a day of healthy eating looks like regardless of what they actually eat. The literature shows the likelihood under reporting increases as the population gets heavier, given there has been a significant increase in the number of obese, surely this must be a factor along with our sedentary lifestyle.

  2. Thanks Sarah. I agree that many more people in 2008, compared with 1997, would easily know what constitutes a healthy diet. If dietary assessment has become more inaccurate over the years, despite improvements in interviewing technique and use of technology, it is certainly a concern since we lean so heavily on these results. I would love to hear what the researchers themselves would recommend. Subjects wearing cameras that take a photo every 40 seconds is an option recently discussed at a conference I attended, but my concern with that technique is that people will still modify their behaviour for the duration of the collection period.

  3. I believe the idea that physical activity levels have dropped is valid. Throughout westernized nations, the time spent in front of a computer screen–both at home and work–is staggering (and has certainly increased since 1997). Even since 2006/07 (when Facebook opened shop), we spend an ever-increasing amount of time in front of computer screens. Another thing to consider might be the aging of the population. Increased stress levels among the population about various things (perhaps up to, and including diet) could also be a culprit for expanding waistlines despite a better overall diet.

  4. A very good point Kyle. It makes me feel old to know facebook has only been around since 2006/07. As far as I know the trend to gradually get bigger around the middle with age is not a new phenomenon, so the ageing population is definitely a key contributor to the higher average population BMI, in my view. Though we do seem to be getting bigger younger, which is where the sedentary behaviour and screen time is a big issue.
    Stress also has a major role to play in our food environment. I suspect this is a key determinant for why we demand convenience and fast foods. Telling people not to eat convenience and fast foods is therefore adding to people’s stress even further. Ensuring the conveniece and fast foods are as nutritious and healthy as they can be – for the same cost – is therefore more likely to have the desired effect.