The edible food that Melbourne consumers waste, by itself, is enough to feed Geelong, Ballarat and Bendigo.
Feeding Melbourne creates more than 900,000 tonnes of edible food waste every year and most of that finds its way into landfill and rots to produce harmful greenhouse gas.
That includes waste before processing, during processing and then the food consumers waste
Food waste in Melbourne is enough to feed two million people for a year and costs the average household $2,200 annually, new University of Melbourne research suggests.
"People need to learn how to use leftovers and cook like their granny used to," University of Melbourne researcher Rachel Carey told AAP.
"It takes a lot of water, energy and land to feed a city - a lot more than people would expect it does - and these vulnerable natural resources underpin our food supply."
The biggest single contribution to the issue is the food consumers waste.
Melbourne's food waste is also responsible for creating 2.5 million tonnes of greenhouse gas emissions each year - most of which is generated by food rotting in landfill.
The wasted food uses 180 gigalitres of water during production.
The Melbourne's Foodprint study, released on Friday, says urgent action is needed to curb the city's food waste to meet the demands of a growing population.
Urban expansion will likely swallow up 16 per cent of Melbourne's farmland by 2050, the study says.