The waste is caused by poor infrastructure and storage facilities, over-strict sell-by dates, "get-one-free" offers, and consumer fussiness, according to the Institution of Mechanical Engineers.
Each year countries around the world produce some four billion tonnes of food.
But between 30pc and 50pc of this total, amounting to 1.2 to two billion tonnes, never gets eaten, says the report Global Food; Waste Not, Want Not.
Irish households were recently estimated to be throwing out up to €1,000 worth of food a year. Fears about foods after their best before dates and the general freshness of the product contributed to the waste.
In the UK, up to 30pc of vegetables are not harvested as their appearance fails to meet the demands of consumers.
Half the food purchased in Europe and the US is thrown away after it is bought.
Vast quantities of water are also wasted in global food production, it is claimed.
Around 550bn cubic metres of water is used to grow crops that never reach the consumer. Producing 1kg of meat is also said to take 20 to 50 times more water than producing the same weight of vegetables.
The demand for water in food production could reach 10 to 13tn cubic metres a year by 2050, the institution said.
This is up to 3.5 times greater than the total amount of fresh water used by humans today.
The institution's Dr Tim Fox said: "The amount of food wasted and lost around the world is staggering. This food could be used to feed the world's growing population -- as well as those in hunger.
"It is also an unnecessary waste of land, water and energy resources."