The World Health Organization on Tuesday urged countries to impose a tax on sugary drinks to battle the growing obesity epidemic and presented new data on the beneficial health effects of such a tax.
A tax on sugary beverages raising their price 20 percent would result in a proportionate reduction in their consumption, the agency said. That would advance the fight against obesity, which has more than doubled since 1980. About half a billion adults were obese in 2014, roughly 11 percent of men and 15 percent of women.
“If governments tax products like sugary drinks, they can reduce suffering and save lives,” Dr. Douglas Bettcher, director of the W.H.O.’s Department for the Prevention of Noncommunicable Diseases, said in a statement. “They can also cut health care costs.”
Obesity began rising in rich countries several decades ago, but is now taking hold in middle-income countries like China and Mexico. Public health experts, alarmed by the trend, are studying policies that countries can enact to fight it.
One way is to tax sugary drinks, like sodas, fruit drinks, energy drinks and iced teas. They have been linked to obesity, diabetes and tooth decay. Supporters of the taxes argue that discouraging consumption of such drinks could help reduce the toll of those ailments.
The W.H.O. has recommended before that countries impose such a tax, most recently in a report this year on preventing childhood obesity. But Tuesday’s report, released at the organization’s headquarters in Geneva, quantifies the effects of such a tax. The agency convened a panel of experts in mid-2015, who produced the numbers after an extensive review of the scientific literature, which included mathematical modeling and studies of actual taxes applied in countries.
The experts also found that subsidies for fresh fruits and vegetables that reduce prices 10 percent to 30 percent can increase consumption of them.
Sugary-drink taxes have been controversial in the United States, where the food industry has fought them. A soda tax in New York City championed by Mayor Michael R. Bloomberg was struck down in the courts, but Philadelphia and Berkeley, Calif., have been successful at carrying out such policies.
A spokesman for the W.H.O., Paul Garwood, said South Africa and Britain were considering taxes. Perhaps the best-known success story is in Mexico, which passed a sugary-drink tax in 2013, prompting a substantial drop in consumption. Hungary has imposed a tax on packaged products with high sugars, salt or caffeine levels.
Dr. Francesco Branca, director of W.H.O.’s Department of Nutrition for Health and Development, said in a statement that sugary drinks are a major source of unnecessary calories, and recommended people drink no more than one serving — about eight ounces — a day.
Sugary drinks have been a problem among children and the poor, and an increase in prices has been particularly effective for those groups, the agency said.
An estimated 42 million children under the age of 5 were overweight or obese last year, an increase of about 11 million over the past 15 years, the agency said. About 48 percent lived in Asia and 25 percent in Africa.