The Liberal government has proposed amendments to a Senate bill that aimed to ban unhealthy food advertising to children under the age of 17 in an attempt to avoid the possibility of a legal challenge.

On Tuesday, as Bill-S-228 entered its second reading in the House of Commons, the Liberal government proposed modifying the definition of “children” from under 17 years old to under 13 years old.

It also asked that the government be required to conduct a mandatory review of the legislation within five years of it coming into force, to ensure that the industry doesn’t shift its marketing efforts overwhelmingly towards older teenagers.

The bill is intended to ban the advertising of foods deemed unhealthy to children in an attempt to reduce the rate of child obesity in Canada. When Bill S-228 was introduced in the Senate last year by Senator Nancy Greene Raine, it had initially identified “children” as those aged under 13, but that definition was later amended to under 17 after the bill went to committee.

“There is a very real potential that this bill could be challenged in its present form under the law,” said Liberal MP Doug Eyolfson, who sponsored the bill in the House. He added that Health Canada consultations have revealed that restrictions aimed at older teenagers “would be subject to considerable legal risks on freedom of expression under the Canadian Charter of Rights and Freedoms.”

Similar restrictions on unhealthy food marketing to children under 13 years of age have existed in Quebec since the passing of the Consumer Protection Act in 1980. However, that law was entangled in a legal battle and wasn’t officially declared constitutional by the Supreme Court until 1989.

Doug Eyolfson said the legal victory in Quebec has set a “strong precedent” for defining children as being under 13 years of age. The government does not want to target older teens and risk “jeopardizing the entire effort,” he said.

In his mandate letter to the new health minister Ginette Petitpas Taylor in October, Prime Minister Justin Trudeau requested that she introduce restrictions on the marketing of unhealthy food and beverages to children “similar to those now in place in Quebec.”

The government has also proposed imposing a mandatory review of the law, based on the experience of Quebec, where advertisers shifted their efforts towards older teenagers once the Consumer Protection Act came into effect, according to Eyolfson.

“The objective of the parliamentary review will be to monitor whether the lower age limit results in increased advertising to teenagers and whether any provisions of the act need to be adjusted to ensure the continued and full protection of our children,” he said.

Some members of parliament have also raised concerns over how the bill will affect sports sponsorships in Canada, such as the Timbits hockey and soccer programs. But the Liberal government has promised to protect such sponsorships, which benefit many children.

“ACA is encouraged by the proposed amendment to Bill S-228,” said Ron Lund, President and CEO of Association of Canadian Advertisers, in an email to strategy. “We look forward to continuing to work with Health Minister Ginette Petitpas Taylor and her officials in the coming months on developing an evidence-based strategy to deal with the very real issue of childhood obesity.”