Thanksgiving is traditionally a big weekend for food drives in Canada. This year, the organizations running them say they're scrambling to find more donations, as workers who have been laid off or have had their hours cut over the past year struggle to keep food on their tables.

The Ontario Association of Food Banks released a report this week saying the number of Ontarians who rely on food banks each month grew by 20 per cent over the past year. Operating expenses at Ontario food banks rose 84 per cent on average, presumably as they try to meet demand.

Factors such as rising unemployment and increasing food prices are to blame, the report says.

"As a result, we have over 350,000 Ontarians turning to food banks," Adam Spence, the association's executive director, told CTV.ca.

At the same time, the province's food banks are receiving fewer donations, Spence said.

"So they are in a very tight squeeze."

Food banks in parts of Ontario that have suffered heavy job losses, such as Windsor, Sarnia and Oshawa, are finding it particularly hard to meet local needs, Spence said.

As of September, the number of unemployed workers in the province had risen by 192,000 compared to a year earlier, Statistics Canada says. Although the province's unemployment rate declined from August to September, over the past year it has risen 2.7 per cent due to layoffs in sectors like manufacturing.

As factories shed workers, Spence said that food banks have been hit twice -- by gaining new clients and losing much needed donors.

The recent closing of an 80-year-old food-manufacturing plant near London, Ont., hurt a number of food banks, Spence said. The plant had been donating about 350,000 pounds of food each year to charities in the province.

Some municipalities have provided food-related charities with new resources to help them cope, Spence said.

For example, the City of Thunder Bay has been debating whether to help the Regional Food Distribution Association of Northwestern Ontario to buy a larger building for its office. The association needs more room to move food, after being overwhelmed by a 36 per cent jump in demand this year.

"But even with that support, a tremendous amount of need remains," Spence said. "At a local level, there are a number of situations where demand has outstripped supply in different places."

Is hunger rising nationally?

Food banks in other provinces say they're facing similar challenges as they try to deal with the effects of the recession, a year on.

Compared to October 2008, there were 420,000 more unemployed workers in the country last month. About 1.5 million Canadians were jobless and looking for work. Many lost their jobs between October 2008 and March 2009, during the worst period of layoffs.

Those who have been unable to find new work appear to be turning in greater numbers to food banks to make ends meet.

Nationally, the number of people using food banks has risen 20 per cent, according to Food Banks Canada. More than 700,000 Canadians now rely on them each month, more than a third of whom are under the age of 18.

"We've never seen that kind of jump so quickly before," said Katharine Schmidt, executive director of Food Banks Canada. "So we've got a lot of food banks across Canada that are really struggling."

"There's often a lag between something changing in a person's life financially, and then them running out of other resources and having to go to a food bank," she said. "We're concerned about the lag, and how many more might be utilizing the resources they currently have, but may soon possibly need some help."

In Alberta, Edmonton's Food Bank has witnessed a much larger jump in demand than the national average. During some months over the past year, the number of people seeking help spiked by 70 per cent, said Marjorie Bencz, the organization's executive director.

Many of the newer clients at Edmonton's Food Bank say they've lost jobs or had hours cut over the last six months, Bencz said.

Her organization is purchasing more food in order to keep up with demand, spending $4,000 on eggs per month instead of $2,000, for example. By August, they had already spent well beyond their budget for the entire year.

Donations have also dropped off, Bencz said. Two corporations that used to contribute a total of $70,000 to the food bank each year have been unable to do so since the recession struck.

"It's been a very challenging year for us so far," Bencz said. "We're just hoping that the economy gets stronger over the next while. We'd like to see less people turning to us."

In Manitoba, Winnipeg Harvest is loading 500 more hampers of food per week than normal. And the number of school-aged children it supports has risen by 23 per cent since September 2008.

"It's a huge jump for us," said David Northcott, Winnipeg Harvest's executive coordinator.

The biggest group of new food bank clients in the city, however, is people who have been receiving employment insurance, Northcott said. As those benefits have expired for jobless workers, more of them are turning to local food handouts.

"The safety net postpones the pain," he said. "That's why, when we saw the layoffs last fall, we're starting to see a jump (in demand) right now."

"The stress is on."

Winnipeg Harvest is also receiving food requests from new families who have recently moved from rural parts of the province to the capital city, where there are more charitable groups to rely on.

"It's an odd time," Northcott said. "It's a very tense time for all Canadians, as well as Winnipegers."