CALGARY - A bold move by Calgary to become the first city in Canada to regulate the use of trans fats in restaurants is just a small step in stemming the tide of the artery-clogging substance, say health experts.

As of Jan. 1, Calgary eateries were banned from cooking with fats and oils that contain more than two per cent trans fats. The same rule applies to all margarines and margarine-based spreads served in those outlets.

Trans fats are cheaper than other oils and have been prized by many restaurants and food manufacturers because they provide a rich texture and longer shelf life. But they've been targeted by health organizations and advocacy groups because of their links to increased risk of coronary heart disease and elevated unhealthy cholesterol levels.

While the move by Calgary is being universally applauded, the fact remains that Canadians for the most part do not eat all their meals at restaurants. Even if every restaurant in Canada were to adopt the trans fat ban, the positive impact would be limited.

"It's one action. Banning trans fat is a good step, but we need to think about education and maybe try to encourage Canadians to eat better," acknowledged Thida Ith, a spokeswoman for the Dietitians of Canada from Montreal.

A 2006 study by the Canadian Council of Food and Nutrition showed that only 20 per cent of Canadians surveyed eat at restaurants more than two or three times a week. But a majority, about 67 per cent, do go to a restaurant or pick up takeout at least once a week.

Figures from the Canadian Heart and Stroke Foundation indicate about 40 per cent of Canadians eat at restaurants on a regular basis.

"I think it's estimated that Canadians eat about 40 per cent of their meals outside of the house, so that's 60 per cent still inside the house," said Stephen Samis, the foundation's director of policy development in Ottawa.

"There's no reason for this poison toxin in our food, and just like the government has decided to ensure we don't have poison toxins in kids' toys, there's no reason for it to be in our food supply either."

Home cooks can encounter trans fats in a wide variety of products, including margarine, shortening, peanut butter, cookies and crackers. Canola oil and olive oil are recommended as fats that are more heart-healthy.

A 2006 federal task force proposed new regulations that would limit levels of trans fats in all foods, a move aimed at decreasing the average trans fat intake of Canadians by at least 55 per cent.

"The government made a decision not to follow that recommendation but rather to put the industry on notice for two years and then regulate it if necessary," said Samis, who worries that more Canadians could die of heart disease in the interim.

"It takes two years to get the regulations in place before you start. Now we would look at four or five years before the regulations are promulgated," worries Samis. "Trans fats cause heart disease. There's a direct link - no one denies it. There's absolutely no redeeming qualities whatsoever. It's only bad."

But the dietitians say we have to be careful not to move ahead too quickly.

"If we ban trans fats, we need to have a substitute for it," said Ith. "We don't want to substitute it with another bad fat. I think there needs to be some studies behind it and what are the alternatives."

Samis said a trans fat ban is also being considered in Toronto.

"I wouldn't be surprised if other cities did follow Calgary's lead. We saw that happen with tobacco control and second-hand smoke," he said. "For the 40 per cent who do eat out regularly, it could prove to be significant."