Sugarcoating the Truth

Does drinking too much soda and other sugary beverages put you at greater risk for serious health problems?

The vast majority of scientists and nutritionists have concluded that the answer is yes, and a growing number of places in the U.S. are considering policies aimed at curbing soda consumption.

But the sugar and beverage industries want you—and lawmakers—to believe the answer is no. And they’ve been working behind the scenes for decades to influence the public debate over sugar consumption by funding scientific studies that give their products a clean bill of health.

Researchers in San Francisco recently released a report that reviewed 15 years of studies about whether soda consumption can lead to obesity and diabetes. Of the 60 studies they examined, 34 were conducted by independent scientists. Every single one of those showed a clear link between drinking soda and developing obesity or diabetes. But the 26 studies done by scientists with financial ties to the beverage industry all found no link between sugary soft drinks and poor health.

“If you look at just the independent studies, it becomes exceedingly clear that these drinks are associated with diabetes and obesity,” says Dr. Dean Schillinger, the lead author of the report and a professor of medicine at the University of California, San Francisco.

The report comes at a time of heightened concern about obesity and growing battles over policies aimed at curbing soda consumption. With 38 percent of U.S. adults and 21 percent of teens considered obese, a handful of cities, including Philadelphia and Berkeley, California, have approved taxes on sugary beverages to discourage people from drinking them. Other places, such as Seattle and the state of West Virginia, are considering following their lead, though lawmakers in New York state and elsewhere have rejected soda taxes.

Why would the sugar and beverage industries pay for scientific studies that claim to show their products are safe? They have a lot to lose if Americans continue to drink less soda (see graph, below). And studies can go a long way toward boosting a claim, especially if no one looks closely at whether the science behind them is solid (see “How to Spot Suspicious Science,” below).

“There’s a huge rash of things that research studies influence,” says Eric Feigl-Ding of the Harvard School of Public Health. “Everything from dietary and environmental guidelines to what your school cafeteria serves for lunch.”

The San Francisco report resulted from a legal dispute between the city and the beverage industry. In 2015, a new city law required that billboards and other ads for sugary drinks carry a warning, similar to those required for tobacco, saying that sugary beverages contribute to obesity, tooth decay, and diabetes.

The beverage industry sued, calling the warnings about health hazards “misleading” and a violation of the industry’s right to free speech. To defend against the lawsuit, which is ongoing, the city hired Schillinger to compile a report assessing the scientific data on sugary drinks and health problems. 

That report is just the latest evidence that the beverage and sugar industries have supported research that downplayed the health hazards of sugar. Last year, a team of scientists, also from the University of California, San Francisco, uncovered hundreds of documents indicating that the Sugar Research Foundation, a trade group now known as the Sugar Association, tried in the 1960s to influence the debate about sugar intake and heart disease. The foundation paid three Harvard University researchers $6,500 total—about $50,000 in today’s dollars—to review existing research on the topic. That review, published in 1967, blamed fat in Americans’ diets for heart disease, one of the leading causes of death in the U.S., but made no mention of sugar.  

The finding helped shape dietary recommendations for decades. The result was that while many Americans tried to cut back on fat, they continued to eat sweets—and drink soda—with abandon. 

The scientific consensus today is that consuming too much sugar causes high blood pressure, abnormal cholesterol levels, heart disease, and obesity. The American Heart Association suggests children eat no more than 25 grams of added sugar* a day. 

“That’s less than [what’s in] a can of regular soda,” says Kimi McAdam, a registered dietitian in Anaheim, California.

As the growing body of science has prompted more cities to consider measures to curb soda consumption, the beverage industry has fought back. It’s filed a lawsuit against Philadelphia’s soda tax, and it has spent millions on ad campaigns against such taxes, which it says hurt the poor. The industry continues to argue that sugary beverages aren’t to blame for Americans’ health problems.  

“Obesity rates have gone up steadily for years at the same time soda consumption has gone down for years,” says William Dermody, a spokesman for the American Beverage Association.

In December, a new study published in a medical journal argued that recent warnings to reduce sugar consumption were based on poor evidence. That report was funded by the International Life Sciences Institute, a group backed by some of the world’s biggest food and drink companies.

That’s exactly the kind of potential conflict that watchdog groups say we should look out for. 

“We need to be wary consumers,” says Michael Jacobson of the Center for Science in the Public Interest. “Look at who funded the study and be skeptical.”