As much as half of the world's food, amounting to two billion tonnes worth, ends up being thrown away, a UK-based report has claimed.
The Institution of Mechanical Engineers said the waste was being caused by poor storage, strict sell-by dates, bulk offers and consumer fussiness.
The study also found that up to 30% of vegetables in the UK were not harvested because of their physical appearance.
The institution's Dr Tim Fox said the level of waste was "staggering".
'Waste of resources'
The report found that between 30% and 50% of the four billion tonnes of food produced around the world each year went to waste.
It suggested that half the food bought in Europe and the US was thrown away.
Dr Fox, head of energy and environment at the Institution of Mechanical Engineers, said: "The amount of food wasted and lost around the world is staggering. This is food that could be used to feed the world's growing population - as well as those in hunger today.
"It is also an unnecessary waste of the land, water and energy resources that were used in the production, processing and distribution of this food.
"The reasons for this situation range from poor engineering and agricultural practices, inadequate transport and storage infrastructure through to supermarkets demanding cosmetically perfect foodstuffs and encouraging consumers to overbuy through buy-one-get-one-free offers."
The report - Global Food; Waste Not, Want Not - also found that huge amounts of water, totalling 550 billion cubic metres, were being used to grow crops that were never eaten.
The institution said the demand for water for food production could reach 10 to 13 trillion cubic metres a year by 2050.
The United Nations predicts there will be an extra three billion mouths to feed by 2075 as the global population swells to 9.5 billion.
Dr Fox said: "As water, land and energy resources come under increasing pressure from competing human demands, engineers have a crucial role to play in preventing food loss and waste by developing more efficient ways of growing, transporting and storing foods.
"But in order for this to happen governments, development agencies and organisation like the UN must work together to help change people's mindsets on waste and discourage wasteful practices by farmers, food producers, supermarkets and consumers."