A tax on sugary drinks to increase the retail price by 20 per cent or more would lower consumption and reduce obesity and other illnesses, according to a new report from the World Health Organization.

On Tuesday, the United Nations health agency called on governments to slap an excise tax on sugar-sweetened beverages such as soda, fruit drinks, sports drinks, energy and vitamin water drinks, sweetened iced tea and lemonade.

Drinking less of the sweet drinks is the best way to curb excessive weight and prevent chronic diseases such as Type 2 diabetes, although fat and salt in processed foods are also at fault, WHO officials said.

"Consumption of free sugars, including products like sugary drinks, is a major factor in the global increase of people suffering from obesity and diabetes," says Dr. Douglas Bettcher, who heads WHO's department for preventing non-communicable diseases. "If governments tax products like sugary drinks, they can reduce suffering and save lives."

Doing so would help fight obesity, Type 2 diabetes and tooth decay, the organization said in a 36-page report timed for World Obesity Day.

Obesity more than doubled worldwide between 1980 and 2014, with 11 per cent of men and 15 per cent of women classified as obese — more than 500 million people, the report said.

Public health officials have long railed about tobacco use. Drawing on those lessons, WHO said imposing or increasing taxes on sugary drinks could reduce consumption.

Instead of pocketing the revenue, WHO suggests governments take the following steps:

  • Subsidize what people pay for fresh fruits and vegetables to improve diets.
  • Increase income for governments to pay for health services.
  • Fund information campaigns.

The tax rate will have to be high enough to reduce consumption to an extent that will generate meaningful health effects, the report's authors said. It would also need to be adjusted to keep in line with inflation.

The health agency has long recommended that people keep intake of sugar to less than 10 per cent of their total energy needs.

The Canadian Diabetes Association urges federal and provincial governments to adopt the measure.

"People with diabetes account for 30 per cent of strokes, 40 per cent of heart attacks, half of kidney failure requiring dialysis and 70 per cent of non-traumatic amputations. This disease has a huge impact on Canadians and on the health-care system and even threatens the sustainability of the health-care system," said Dr. Jan Hux, chief science officer at the Canadian Diabetes Association.

Briefing documents show the federal Revenue Department looked at the implications of a new soda tax prior to this year's budget.

High consumption rates in teen boys

A spokesman for Health Minister Jane Philpott said the government is committed to improving the health and well-being of Canadians.

"We remain open to considering strategies that could make it easier to eat and live well, and we will continue to monitor emerging evidence on the effectiveness of sugar taxes from a public health perspective," he said in an email.

The Dietitians of Canada have also called for an excise tax of 10 to 20 per cent on sugar-sweetened beverages, saying it would lead to annual revenue of $1.8 billion for the government, based on Canadian research.

"We see high rates of consumption continuing in adolescent boys," said Kate Comeau, a spokeswoman for Dietitians of Canada in Halifax. "It's about one pop a day that they're consuming, which adds up to about 40 grams of sugar."

With 10 teaspoons of sugar, that's about 85 per cent of the WHOs recommended limit for the average adult, the dietitians group said.

The tax is "just one option that could be part of a suite of options to help make the healthy choice the easier choice," Comeau said. 

The U.S.-based soft drink industry's lobbying arm — whose members include Coca-Cola Co, Pepsico Inc and Red Bull — strongly disagreed with what it called "discriminatory taxation."

"Just taxing one small segment of consumers' consumption is not going to move the needle on obesity," said Jim Goetz, president of the Canadian Beverage Association. 

Wherever these taxes have been introduced there have been job losses, said the Canadian Beverage Association, which said its members employ 60,000 people. 

With files from CBC's Melanie Glanz, Associated Press and Reuters