Meat, fish, bones, pizza boxes and other foods were added to the list allowed in Vancouverites' compost bins Tuesday following an announcement by Mayor Gregor Robertson, who expanded a food scraps program launched two years ago.

It's the latest change in the Vancouver definition of compost materials. For now, the additions only apply for duplexes and houses, but plans are in place to implement the program to businesses, condos and apartments.

"Everybody needs to step up and be more responsible with their waste," Robertson told reporters during a demonstration.

"This is a big shift we're going to see right across the region."

Robertson said materials are taken to composting facilities across the region, where the junk is turned into dirt, potentially cutting the number of food scraps in landfills.

He estimates nearly 40% of current garbage in landfills are compost materials.

Changes to collection schedules are expected in spring 2013, when regular garbage pickup will be reduced to twice monthly, with weekly "green bin" pickups.

Robertson also urges residents plastics - even if labelled biodegradable - are not permitted in the compost bins, which traditionally hold yard waste, as this could ruin compost batches.

"If we remove all food scraps and compostables from Vancouver's landfill, it reduces pollution by the same amount as taking 10,000 cars off the road."