Artificial trans fats were officially banned from Canada's food supply on Monday — a move that comes almost 15 years after a majority of MPs voted in support of it.

The ban saw Health Canada add partially hydrogenated oils — the main source of trans fats in foods — to its "List of Contaminants and Other Adulterating Substances."

The oils are used in the production of pastries, other baked goods and some packaged goods in order to extend shelf life. But they also raise levels of low-density lipoprotein (LDL), or "bad," cholesterol in the blood, while lowering levels of high-density lipoprotein (HDL), or "good," cholesterol.

"This is a very important milestone in terms of nutrition policy in Canada," said Manuel Arango, the director of health policy and advocacy at the Heart and Stroke Foundation.

"What it means is that, moving forward, industry will not be able to manufacture or use partially hydrogenated oils that create artificial trans fats in the food supply. It will be completely prohibited in Canada."

One year ago, Health Minister Ginette Petitpas Taylor told the food industry that a ban would be coming, giving it enough time to find suitable alternatives.

"As minister of health, I am very concerned with the rise in heart disease, which is one of the leading causes of death in Canada," Petipas Taylor said in a statement on Monday. "Health Canada's ban on partially hydrogenated oils in the food supply is part of the government of Canada's action to help protect Canadians from diet-related chronic disease."

With the ban in effect, it is now illegal for manufacturers to add artificial trans fats to their products. The ban applies to all foods produced for sale in the country, including imported products and foods prepared and served in restaurants and food service establishments.

Trans fats as 'heart-clogging'

Artificial trans fat is made when hydrogen is added to a liquid vegetable oil, giving it a solid consistency. Trans fats are typically used in foods that can be hard to resist — like pastries, french fries, doughnuts and popcorn.

But they can take a toll on the heart — Arango describes artificial trans fats as "heart-clogging." And research has shown that a ban could prevent 12,000 heart attacks over a 20-year period in Canada.

Trans fats have been under fire for years.

In 2006, a government task force issued a report urging regulation of trans fats, noting that the average intake of Canadians should decrease by at least 55 per cent. A year later, in 2007, the food industry was given two years to voluntarily lower artificial trans fats levels in products or face government regulation, which didn't immediately come.

After the U.S. announced a ban on trans fats in 2015 — something fully implemented earlier this year — a newly elected Justin Trudeau asked his health minister to look into tougher regulations, ultimately leading to the ban.

Foods like french fries can be cooked in partially hydrogenated vegetable oil, the primary source of artificial trans fats. (Carlos Osorio/Associated Press)

Although levels have steadily gone down, there's still a lot of trans fat-loaded food out there.

Even with the ban in place, artificial trans fats won't be completely gone; they'll still be in already produced foods on store shelves across the country.

As Arango explained it, if food containing trans fats was manufactured before Monday, that food can stay on store shelves — perhaps "for a couple of years" — before being removed.

'False good news'

Retailers will be given a grace period of two years to clear the inventory already on store shelves.

"The consumers might still find some products on the shelves that will have trans fats that would have been produced before this [ban] came into place," a Health Canada official told CBC News prior to today's announcement.

"Health Canada estimates that within three years, there will not be any kind of trans fat products on the shelves."

The Quebec Coalition on Weight Issues says it is disappointed with the two-year reprieve. In a written statement, it said the new delay is both "shocking, and "insulting to Canadians."

"It has been more than 10 years since the industrial trans fat limits were unveiled to the food industry. One year after the announcement of the regulation, it is incredible that they are given time to sell foods that contain an ingredient now classified as unsafe for health!" wrote the director of Weight Coalition, Corinne Voyer.

Still, Arango, of the Heart and Stroke Foundation, says he sees the impending ban as being a "glass half-full."

"If you look at the long history of the battle against trans fats, it wasn't won overnight. But this puts us on a very clear path toward the complete elimination of trans fats," he said. "[In] roughly two years, there will be nothing left in Canada — virtually nothing. So that's pretty significant."

As for obesity expert Dr. Yoni Freedhoff, who has been a longtime critic of trans fats, his reaction to the new regulations — and the fact some trans fats will remain on store shelves for a while longer — was more muted.

"Some action is better than no action," he said.

With files from CBC's Melanie Glanz