The United Nations is leading World Food Day celebrations by warning against food waste and stressing the importance of healthy diets amid rising obesity. It says around 840 million people go hungry while a third of the food produced globally goes to waste.

According to the Rome-based UN Food and Agriculture Organisation, halving the amount of food wasted would mean having to raise world food production by 32 percent to feed the world’s population in 2050, instead of the 60 percent currently estimated.

The UN agency also warned about the high costs that malnutrition and poorly-balanced diets impose on society -- from towering health care bills to lost productivity.

About two billion people in the world lack vitamins and minerals that are essential for good health while another billion people are overweight.