MONTREAL -- Liberal Leader Philippe Couillard is standing by his claim that $75 is enough for a family of three to feed itself for a week, saying it just requires a lot of work and an eye for bargains.

When presented the grocery question out of the blue Thursday by a radio host, Couillard answered it would be possible to feed an adult and two teenagers on that amount, acknowledging later to reporters the menu would lack meat and variety.

Asked again Friday on Montreal's 98.5 FM, Couillard said he wished people didn't have to live on such a tight budget, but he knows some who do.

"You look through all the flyers, and you shop only for what is on sale," Couillard said. "It's almost a full-time job."

He gave the example of a roast pork bought on special that is used in macaroni the next day, shepherd's pie the third day and sandwiches the day after.

One of the authors of Canada's Food Price Report said $75 would not suffice.

Dalhousie University Prof. Sylvain Charlebois said that in 2017 the bare minimum grocery bill for a Quebec family of two adults and two children, including one teen, would have been $149 a week, double the amount in Couillard's example for three people.

"If you live on your own, maybe, but if you have children in your home who are growing, it's absolutely impossible," Charlebois said.

The only way to make it work on $75 would be to resort to food banks, he said. Otherwise the family would "end up with a diet that has no variety, and the nutritional value would be severely compromised."

Accused by his political opponents of being out of touch, Couillard told reporters Friday he did not regret his answer, adding the debate has shed a light on the need to fight poverty.

"No, I said the truth," Couillard said. "The question was, 'Is it feasible?' Yes it's feasible. I know people who do that. Is it good? No."

It is not the first time a question about groceries has tripped up a politician.

In the United States, George H.W. Bush admitted in a 1992 presidential debate with Bill Clinton and Ross Perot he didn't know how much a gallon of milk cost.

In 2007, Republican presidential candidate Rudy Giuliani was way off when quizzed on the cost of a gallon of milk and a loaf of bread.

Just last month, U.S. President Donald Trump claimed erroneously that photo identification is needed to buy groceries.

Sam Watts, managing director of a Montreal food bank that provides groceries to 19,000 clients a month, said a family's diet would be limited on $75 a week.

"The issue is healthy food," said Watts, who works at The Welcome Hall Mission.

"Someone could eat macaroni seven days a week, but that's not a good diet, and the result is it would create other problems the health system would have to resolve."

Wendy Gariepy of the West Island Mission, which serves Montreal's western communities, called a $75 grocery budget "really tight" and put the mimimum closer to $125.

A Quebec family of four last year spent on average $233 a week on groceries, Charlebois said, the third-most per capita after Saskatchewan and British Columbia.

"But in Quebec, salaries are much lower, so the percentage of the food budget based on income is much higher than anywhere else," Charlebois added.