There is no question that our food-consumption habits (or lack of) generate enormous amounts of waste, but a new study from the University of Edinburgh is laying claim to exactly how much. The researchers estimate that around one fifth of the food made available to us is lost, either by ending up in the trash or by us chowing down on food we simply don't need to eat.

Scientists at Edinburgh arrived at these figures after examining ten key stages in the global food system, such as food consumption, crop production and harvesting. The data was mostly taken from the UN's Food and Agriculture Organization and reveals that more food is going to waste than previously thought.

In total, almost half of harvested crops, around 2.1 billion tons, are lost through a combination of consumer waste, over-consumption and wastage prior to consumption through inefficient production processes. A glaring example of the latter was found in livestock production which amounts to 40 percent of total harvested crop loss, as lead research Peter Alexander tells us.

"In aggregate, all livestock consume 1.08 billion tons of feed (dry matter), but produce just 240 million of meat, milk and eggs (again dry matter)," he explains. "The livestock also graze grassland and consume forage crops, which brings the total livestock inputs to 4 billion tons."

But perhaps more startling are the figures relating to wastage and over-eating, which the researchers define as food consumption in excess of nutritional requirements. The researchers conclude that the world population consumes around 10 percent more food than it needs, which combines with the nine percent that is thrown away to equal to the one-fifth figure.

This is a concern in light of the world's growing population and the search to feed it in sustainable ways. An MIT study from 2014, for example, estimated that we'll need about 50 percent more food by 2050 to due population growth and dietary trends. The Edinburgh team suggests people start to lighten the load by consuming less animal products, reducing waste and eating only what their nutritional needs require.

The study was published in the journal Agricultural Systems.