CHICAGO: Cleaning your plate may not help feed starving children today, but that time-worn advice of mothers everywhere could cut food waste, help the environment and make it easier to feed the world's growing population.
Hard data is still being collected, but experts at the Reuters Food and Agriculture Summit in Chicago this week said an estimated 30 per cent to 50 per cent of food produced in the world goes uneaten.
But the impact of food waste stretches far beyond the kitchen.
'No matter how sustainable the farming is, if the food's not getting eaten, it's not sustainable and it's not a good use of our resources.'
Sustainable agriculture specialist Dana Gunders at the US Natural Resources Defence Council
Agriculture is the world's largest user of water, a big consumer of energy and chemicals, and major emitter of greenhouse gases during production, distribution and landfill decay.
Experts said reducing waste is a simple way to cut stress on the environment while easing pressure on farmers, who will be called on to feed an expected nine billion people around the world in 2050, versus nearly seven billion today.
'No matter how sustainable the farming is, if the food's not getting eaten, it's not sustainable,' said sustainable agriculture specialist Dana Gunders, who is with environmental action group Natural Resources Defence Council (NRDC).
The average American throws away 15kg of food each month - about US$40 (S$50) worth - according to the NRDC.
'We forget we have all these fresh fruits and vegetables, and at the end of the week we have to throw them away,' said Ms Esther Gove, a mother of three young children in the US state of Maine.
'Now, I don't buy as much fresh produce as I used to.'
High food prices are another factor, since some people cannot afford the food that is produced, said Mr Patrick Woodall, research director and senior policy advocate for Food and Water Watch.
'It's not a situation where you have to massively ramp up production,' Mr Woodall told the Reuters Summit.
'Even in 2008, when there were hunger riots around the world, there was enough food to feed people, it was just too expensive.'
Europe is a leader in tackling food waste, but the United States is catching on, too, as producers, facing tepid sales growth, look to control costs.
For example, a General Mills pizza plant in the US found a way to use heat to make toppings stick to frozen pizzas better. The system is expected to prevent thousands of pounds of cheese and other pizza toppings from going to waste each year.
Experts have also floated a variety of recommended fixes. They say clarifying 'sell by' and 'use by' dates could help consumers avoid throwing food in the garbage too soon. Some food could be 'rescued' and used in soup kitchens, while certain leftovers could be used as animal feed.
Increasing composting could boost soil health and drought resistance, while also easing the burden on landfills and reducing decomposition of garbage into the greenhouse gas methane.
Researchers said people of every age - especially children - contribute to the food waste problem.
Ms Gove said she has cut waste by starting with smaller meal portions for her children, who get more only when they ask.