Make a shopping list and buy "funny fruit," it will cut food waste and help "shape a sustainable future," the United Nations Environment Programme and Food and Agriculture Organzation said on Tuesday.

The UNEP, FAO and partners unveiled a campaign dubbed "Think-Eat-Save Reduce Your Foodprint" to change global practices that result in the loss of 1.3 billion tonnes of food each year.

The programme is aimed primarily at consumers, food retailers and the hotel and restaurant industry, and is based on three recommended actions, think, eat, and save.

"In a world of seven billion people, set to grow to nine billion by 2050, wasting food makes no sense ? economically, environmentally and ethically," a statement quoted UN Under-Secretary-General and UNEP Executive Director Achim Steiner as saying.

FAO Director General Jose Graziano da Silva pointed out that in industrialised nations, around 300 million tonnes of food are wasted each year, "because producers, retailers and consumers discard food that is still fit for consumption."

That is more food than is produced in sub-Saharan Africa, and is enough to feed the estimated 830 million people who now go hungry worldwide, he added.

The programme estimates the overall cost of wasted food at about $1.0 trillion (751 billion euros) per year, with most losses occuring in production stages such as harvesting, processing and distribution.

Consumers can participate in a global effort by respecting a few simple recommendations, the agencies said.

Planning meals, making shopping lists and avoiding impulse buying helps, as does staying alert "to marketing tricks that lead you to buy more food than you need."

Another good idea is to "buy funny fruit" or vegetables that would otherwise be thrown out because their size, shape or colour do not meet accustomed standards.

Paying attention to expiry dates and "zeroing down your fridge" with recipes that use up food set to go bad helps as well, as does freezing food, asking restaurants for smaller portions, eating leftovers, composting food or donating it to food banks, soup kitchens and shelters.

Retailers can offer discounts for food that is nearing its sell-by date, standardizing labels and donating more food.

Restaurants were urged to "limit menu choices and introduce flexible portioning," auditing how much food they waste, and setting up "staff engagement programmes."

Finally, an Internet site, is to serve as a global platform for sharing information on other initiatives that people come up with.