The wealthier we get, the more food we waste, according to new research.

The Dutch scientists behind the research also warn that food waste by consumers in some developing countries could be about to explode, as these nations become more affluent.

Key points: Global consumer food waste is a bigger problem than previously thought

Global consumer food waste is a bigger problem than previously thought It increases sharply when daily expenditure exceeds $10 a day

It increases sharply when daily expenditure exceeds $10 a day Local experts say there is not enough data to draw firm conclusions about Australia

Given the contribution of food production to greenhouse emissions, this could have significant effects.

"It's all about how you value food," said Monika van den Bos Verma, an applied economist from Wageningen University and Research in The Netherlands.

"Food waste is a luxury. Poor people cannot afford to waste."

The UN Food and Agriculture Organisation (FAO) estimates one third of food produced for human consumption is uneaten, but relatively little is known about the cause of this waste.

This latest research, by Dr van den Bos Verma and colleagues, is the first to look at the role of consumer affluence on food waste. The findings are published today in the journal PLOS ONE.

Rather than relying on surveys, which can mislead because people don't tend to keep very good records of how much food they waste, the researchers used a different technique.

Working out a country's food waste

Food waste is the difference between the food available to you and the food you actually consume.

The researchers inferred how much people were eating based on their bodyweight and how active they were.

"For most people, what you eat shows up on your body," Dr van den Bos Verma said.

She and colleagues used reports from the WHO and other sources to get average figures for 63 countries that include over 60 per cent of the world's population.

Map of the world showing how rich countries (pink) waste more food than poorer countries (green). ( Supplied: Monika van den Bos )

They then compared the food consumption to the amount of food available in each country.

The difference gave them a measure of food waste, expressed in kilocalories per day per person (Kcal/day/capita) in each country.

Next they saw how this related to the average affluence of consumers in each country, using figures obtained from the World Bank.

They found that once people were spending over US$6.70 (about $10) a day their food waste increased sharply, until higher wealth levels where it increased more slowly.

While $10 a day doesn't sound like much, half of Asia Pacific and more than half of Africa is below that threshold, Dr van den Bos Verma said.

"It's not a lot of money for rich nations but it's a lot of money for those people."

Dr van den Bos Verma said as people grew richer they valued food less because it was relatively cheap for them.

"Currently in rich countries you only spend 10 per cent of your income or even less on food."

Food waste time bomb

Dr van den Bos Verma said while low income countries had a right to grow their wealth, food waste could become a problem as it is in developed countries unless care was taken.

"The rich countries have the disease of food waste. They need a cure but currently growing countries will get the problem of food waste and they need a prevention."

Dr van den Bos Verma said countries like Indonesia and the Philippines were close to the threshold and ripe for an "explosion" in food waste.

By looking at the relationship between the affluence of consumers and the food they waste, researchers concluded that the FAO estimates for global food waste were less than half what they should be.

Food waste is a "luxury" the poor can't afford. ( Getty Images: hadynyah )

Data collected by the FAO suggest the average global consumer wastes 214 Kcal/day/capita, but the new study found the figure was more like 527 Kcal/day/capita.

In Australia the figure is over 1,300 and in the US it is over 1,500.

"We are creating a lot more waste than we think we are," Dr van den Bos Verma said, adding this had implications for climate change.

Food security and health were also put at risk by food waste, she added.

Jenni Downes, a social scientist from the Monash University Sustainable Development Institute, said the study was very theoretical and had a number of limitations.

And she emphasised that the energy measure of food waste used by the researchers (Kcal/day/capita) could not necessarily be equated to volume.

"A cake has very different calorific value to a carrot."

But she welcomed the strength of the link shown by the study between affluence and food waste.

"To me that's what's really valuable about this study," Ms Downes said, agreeing there needed to be a focus on food waste prevention in developing countries as well as more developed ones.



In developing countries, more food waste occurred at the production end than in developed countries, Ms Downes said, while less occurred at the consumption end.

It is possible that as consumer waste increases in developing countries it could be at least partly offset by a decrease in waste at the production end, she said.

What about Australians?

Steven Lapidge, CEO of the Fight Food Waste CRC said the new findings on the role of affluence in generating food waste were not surprising.

Neither were the findings that we have underestimated the nature of the global food waste problem, he said.

"The research suggests that we have a global problem significantly larger than we first thought, which is of concern."

But Dr Lapidge urged caution in interpreting the new findings, emphasising that the food waste figures for Australia were "only an indication".

"We shouldn't say that Australians are wasting twice as much food because we don't have that data.

"Whether we are now wasting more or less we simply don't know. There has only been one baseline study done in Australia that was published. Repeating this study will help determine this."

Dr Lapidge also said environmental consciousness was growing, including in Indonesia, which has instigated a large food waste reduction program.

Still, the pressure is on.

"Most of the developing world is committed to ... halving food waste by 2030. If these recent predictions are accurate that's just made our task a lot harder."