Produce grown in the UK that does not meet retailer standards on size or shape or is blemished is often used for animal feed or simply ploughed back into the ground even though it is edible, with as much as 40% of a crop rejected.
The report, commissioned by the UK's global food security programme, also showed that the average household throws away more than 5kg (11lbs) food per week, and nearly two thirds of that waste is avoidable.
The waste costs £480 a year per household on average, and £680 per family.
Professor Tim Benton, global food security champion, said: "Over five million people in the UK live in deep poverty, where basic food provision is a daily challenge."
He added: "At the same time, 15 million tonnes of food is wasted annually, with nearly half discarded within UK households."