New research from New Zealand has found that over-eating rather than lack of physical activity, is why Kiwis are pilling on the excess kilos.
The researchers from Auckland University of Technology (AUT) also say nutritious food is more expensive, rates of obesity are higher in the those who are poorer and physical activity can not fully compensate for consuming too many calories.
Professor of Nutrition Elaine Rush, is the co-author of the study which examined the relationship between ‘energy in’ and ‘energy out’, using measurements made in New Zealand, the U.S. and the Netherlands and she says 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.
Professor Rush says quite simply - over-eating and eating the wrong, energy dense foods which are full of calories, means children in New Zealand - like those in the United States - have become on average 4kg heavier over the past three decades and adults 8kg heavier.
The 2006 – 2007 New Zealand Health Survey found that 1 in 4 adult New Zealanders are obese.
Professor Rush says their research found the rates were higher for the poorer proportion of those tested - she says nutritious food is generally more expensive than less healthy food and puts the poorer section of the population at greater risk of obesity.
So called ‘affordable foods' says Professor Rush are often full of fat or empty calories such as white bread, full-fat milk and cuts of meat with a high fat content, and often people are left malnourished and hungry.
For the study the researchers calculated what adults should currently weigh based on their higher food intake, and compared this to their actual weight - if they weighed more than projected, this would suggest a drop in physical activity - but in fact the researchers found that adults weighed less than could be expected from their diet and Professor Rush says this suggests, if anything, over that period of time, the adults may have been increasing their physical activity, not decreasing it.
As the rates for children were on a par with the adults, the researchers came to the conclusion that changes in physical activity had little or no impact on children growing fatter.
Prior to the study, the researchers assumed that people were in general over-eating by about 100 calories a day, however, the results were far more alarming - it was found that between 350 – 500 extra calories a day more than is needed is being consumed by many.
In real terms this means says Rush that 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.
Professor Rush says in today's society, walking an extra two, to two-and-a-half hours a day to burn off the extra calories, is not really an option and we need to be realistic about what physical activity alone can achieve.
Professor Rush says the study shows that in order to influence the underlying drivers of obesity we should be looking more to the ‘energy in’ side than the physical activity side as over-eating or eating highly calorific foods are key players in obesity.
Nevertheless says Professor Rush this does not say that throughout life, physical activity is not essential for health and quality of life.