As health advocates push for Canada to adopt a tax on sugar, critics say such a move would unfairly target certain companies and wouldn’t necessarily spur a drop in obesity rates.

A group of Canadian dieticians is calling for the government to charge a 20 per cent tax on food and drinks with added sugar. Recent Statistic Canada reports suggest that about one in five Canadian adults are obese.

“The majority of sugar is coming from sugar-sweetened beverages. So it’s a place for us to start in terms of reducing consumption,” Kate Comeau, a dietitian and spokesperson for Dietitians of Canada, told CTV News.

The idea comes from Mexico, where over 70 per cent of adults are overweight or obese. In an attempt to curb the health crisis, the Mexican government brought in a 10 per cent tax on sugary foods in 2014.

One year later, sales of the taxed products dropped 12 per cent, according to one study. Mexico also saw a general increase in water consumption, an indicator that “is really positive in terms of preventing chronic disease,” Comeau said.

India, the U.K. and the Philippines have toyed with adopting a similar policy. The U.K. in particular has struggled with obesity, with one report suggesting that 66 per cent of men and 57 per cent of women over the age of 20 are obese.

But critics say that, while sales in Mexico dropped, there has yet to be a study that makes a definitive link between the country’s sugar tax and a drop in obesity rates.

One study found that Mexico’s tax only cut about six calories per citizen per day. (Mexico has a population of about 122 million.)

“A lot of this stuff basically makes them feel good that they’re actually doing something but it won’t help with reducing weight overall,” said Patrick Luciani, author of “XXL: Obesity and the Limits of Shame.”

Some companies say it’s unfair to blame one particular product for obesity rates, which could also be linked to inactivity levels or large portion sizes.

A few beverage companies have made efforts to cut sugar levels over the years.

“The beverage industry as a whole has also reduced the amount of calories Canadians consume by approximately 20 per cent in the last 10 years,” said Jim Goetz, president of the Canadian Beverage Association.

Consumption of high levels of sugar has been linked to diabetes, cardiovascular disease and weight-related conditions.

With a report from CTV medical specialist Avis Favaro