Officials at the Centers for Disease Control and Prevention have their hands full these days. An epidemic of obesity has hit Americans hard, raising the risks for heart disease, stroke, type 2 diabetes and certain types of cancer. Childhood obesity is a particular prevalent problem.

Last year, World Health Organization (WHO) Director General Margaret Chan said the marketing of full-sugar soft drinks was a key contributor to rising obesity rates among children, suggesting restrictions on sugar-rich beverage consumption.

Though the beverage industry has strongly objected, several U.S. cities have been passing, or trying to pass, taxes on sugary sodas to discourage consumption. Since Berkeley, California became the first U.S. city to levy a soda tax in 2014, consumption dropped more than 20 percent in some areas of the city, according to a report published August 23 by the American Journal of Public Health.

A Mexican soda tax correlated with a similar drop in soda purchases, according to research published earlier this year. One would expect the efforts would be heartily applauded by the CDC. And indeed, earlier this year a CDC research report said more aggressive measures were needed to convince Americans to cut back on sugary drinks.

But behind the scenes, mounting evidence suggests that rather than cracking down on the soda industry, high-ranking officials within the CDC’s National Center for Chronic Disease Prevention and Health Promotion are instead cozying up to beverage giant Coca-Cola and its industry allies, even in some cases aiding the industry as it argues that sodas are not to blame.

At least one internal ethics complaint over industry influence was lodged this month, according to a source inside the CDC. And more may be coming as a group of scientists within the CDC reportedly are attempting to push back against a culture cultivating close ties with corporate interests.