The lecture, the seventh in the annual series, was delivered by food industry veteran and farmer Lord Christopher Haskins of Skidby on the subject Are the Malthusian chickens coming home to roost?
Reverend Malthus, an 18th century cleric, predicted that that there would be a crisis in food supply as a result of swift population growth.
Although his solution - to restrict the right of poor people to breed - was thankfully dismissed, his fears are echoed by the United Nation's Food and Agriculture Organization, which predicts that the world's population will increase by 50 per cent by 2050.
"Put simply, we waste far too much food, energy and foods, and we eat too much," said Lord Haskins, who linked this issue to ensuring global food supply and combating climate change.
Lord Haskins hazarded that as much of 50 per cent goes to waste.
"If we could save even half of this, we would solve the Malthusian question, and we would also make a huge contribution to the environment by reducing the huge tonnage of greenhouse gases created in the production and disposal of this unnecessary waste."
Moreover, in the UK 30 per cent of food bought in shops is wasted in homes, leading Lord Haskins to condemn 'buy one get one free promotions', especially in perishable products, as "a social evil".
He noted several other ways in which supermarkets are contributing to the trend towards waste and greed.
For instance, shelves are over-stocked for reasons of presentation, and slightly blemished fruit and vegetables are rejected because "fussy" consumers will not pick them.
Some of the shelf lives, he said, are "unduly short because they are designed to protect the most idiotic of consumers who leave their cartons of cream on the seat of a car for several hours in a heatwave".
Moreover, Lord Haskins said that supermarkets contribute to waste at a supplier level by giving too little notice of orders and reserving the right to cancel at the last minute.
Although there are now better control systems in the affluent food chain, there are still many failures that result in waste.
By contrast, in some parts of the developing world these controls do not exist at all, which not only creates waste but also a public health hazard.
In addition, Lord Haskins said that the rising tide of overweight is closely linked to affluence. Rather than reducing calorie intake to offset the sedentary hours spent in front of a computer screen, consumers are actually eating more - and diets are tended to be more heavily weighted towards previously unaffordable meat.
Whilst not suggesting that the world should go vegetarian, he said we should eat less meat than we do for a number of reasons.
These include the implications on human health of eating too much meat; demand for feedstuffs leading to "possibly intractable" health and welfare problems for the livestock industry; the inefficiency of converting animal-derived protein; and the role of animal bi-products in global warming.
Lord Haskins jested that one cow produces the same level of emission as one 4x4 vehicle.
"The conclusion one has to come to is that the only ethical diet is the vegetarian one, and that livestock farmers, including the whole organic movement, are not contributing to a solution of the problem."
The 2008 City Food Lecture was sponsored by the UK's seven food livery companies (The Worshipful Companies of Bakers, Butchers, Cooks, Farmers, Fishmongers, Fruiters and Poulters), The Real Good Food Company, Nestle, Lockwood Press and Winter Berries.