The study also found that rates of obesity
were higher in the poorer section of those
tested - nutritious food is more expensive
than less healthy food.
Image: iStockphoto
Over-eating, not lack of physical activity, explains why New Zealanders are putting on excess weight, claims Auckland University of Technology (AUT) University’s Professor of Nutrition Elaine Rush, and physical activity can not fully compensate for consuming excess calories.
Professor Rush co-authored a study on the relationship between ‘energy in’ and ‘energy out’, using measurements made in New Zealand, the US and the Netherlands, which was unveiled at the international obesity conference in Amsterdam this month.
‘There is no evidence that a considerable reduction in physical activity has been a contributor to the obesity epidemic in New Zealand or other countries,’ says Rush.
‘Put simply,’ she says ‘We are over-eating and eating the wrong, energy dense foods which are full of calories.’
Rush says that similar to the United States, New Zealand children have grown on average 4kg heavier over the past three decades with adults putting on an extra 8kg.
These rates were higher for the poorer proportion of those tested, with Rush citing that ‘affordable foods tended to be full of fat or empty calories such as white bread, full-fat milk and cuts of meat with a high fat content, and often left people malnourished and hungry.’
‘Nutritious food is generally more expensive than less healthy food and puts the poorer section of our population at greater risk of obesity.’
The study calculated what adults should weigh today based on their current, higher food intake, and compared this to their actual weight.
If they weighed more than projected, this would suggest a drop in physical activity. In fact, researchers found that adults weighed less than could be expected from their diet, ‘which means that if anything over that period of time, the adults may have been increasing their physical activity, not decreasing it,’ says Rush.
Rates for children were on a par with the adults, leading researchers to conclude that changes in physical activity had no or little impact on children growing fatter.
Before the study, researchers held the belief that we were over-eating by about 100 calories a day, however, the results were more alarming.
‘We are consuming between 350 – 500 extra calories a day than we need,’ explains Rush. ‘Children would have to cut their intake by about 350 calories a day - equal to one can of fizzy drink and a small chocolate bar, and adults 500 calories – the equivalent of a large burger.
‘In a time poor society, walking an extra two, to two-and-a-half hours a day to burn off the extra calories, is not really an option,’ added Rush. ‘We need to be realistic about what physical activity alone can achieve.
‘What this study is showing,’ explains Rush ‘Is that to influence the underlying drivers of obesity we should be looking more to the ‘energy in’ side than the physical activity side.
‘Over-eating or eating highly calorific foods are key players in obesity,’ she adds. ‘That’s not to say that throughout life, physical activity is not essential for health and quality of life.’
The 2006 – 2007 New Zealand Health Survey, A Portrait of Health, states that 1 in 4 adult New Zealanders are obese.
Editor's Note: Original news release can be found here.
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