CrossFit Inc.’s founder and CEO Greg Glassman has a message for Washington lawmakers: Get soda out of medical research.

Propelled by recent evidence that the sugar industry once influenced nutrition guidelines and by apparent ties between Coca-Cola and a Centers for Disease Control and Prevention official, Glassman spoke on Capitol Hill Tuesday about how Congress should work to keep soda companies from influencing medical research. While it’s no surprise that Glassman, creator of a high-intensity fitness plan, calls soda a “toxin,” the latest questions about transparency also provide ammunition against groups that have challenged his business and methods.

“I’m not trying to put soda out of business,” Glassman said earlier in the day at a breakfast held by the Cato Institute, a Libertarian think tank, where he admitted he occasionally drinks Diet Coke. “I just want them out of the health sciences.”

Some fitness groups with soda company ties have a history of animosity with CrossFit. For instance, in 2014 CrossFitsued the National Strength and Conditioning Association over a study the group published in its journal that claimed a high number of CrossFit participants quit before completing the program because of injury or overuse. CrossFit’s lawyers said the findings were false, and that the group was trying to discredit the fitness giant because CrossFit has brought competition to the market.

The National Strength and Conditioning Association declined to comment, citing ongoing litigation. While it issued an erratum, or correction, in September, it also concluded, “This change does not affect the overall conclusion of the article.”

The group receives sponsorship for other activities from PepsiCo-owned Gatorade Company, as well as its affiliated Gatorade Sports Science Institute.

The American Beverage Association said in a statement that it sponsors research that seeks to answer scientific questions about the products its members make and their ingredients.

“The research findings contribute to the body of scientific knowledge about beverages and is intended to help provide people with the information they need to make informed choices, as well as inform regulatory agency and other stakeholder assessments,” the association said in an email, adding that its mission was to “inform and clarify discussion through scientific inquiry, and is held to the highest standards of integrity.”

The packed Hill event Tuesday was hosted with Rep. Darrell Issa, R-Calif., to spotlight fitness and nutrition and recognize Marines who use the program and whom the congressman represents, his spokesman said. There was no indication given as to whether Issa would consider introducing legislation regarding research transparency.

Glassman, 60, who wore a T-shirt, faded jeans and a backwards baseball cap, called for Congress to weigh independent research more stringently when it’s sponsored by soda companies, among other measures.

He has also sought to influence state laws. In California, he supported a bill that would have required warning labels on soda products, but it failed in committee.

Glassman, who defined himself as having Libertarian tendencies, admits his position may be unusual for those with similar political leanings, but says he believes people don’t know how dangerous soda is to their health.

He said he was taking on the cause because “it’s the right thing to do.”

But Patrick McCarty, a CrossFit coach in Loveland, Ohio, who has been critical of the business side of CrossFit on his blog, says other motivations are at play.

He notes the American College of Sports Medicine has pushed for legislation that would require certain trainers to be licensed through their program, even though CrossFit licenses its own coaches and additional training could be costly. The Gatorade Sports Science Institute is a sponsor of the group and in past years the group also has partnered with Coca-Cola, reveals a search on the company’s website.

McCarty said in a direct message sent through Twitter that Glassman has said since 2002 that the CrossFit diet shouldn’t include sugar, but adds, “that has not really been a cornerstone of the CrossFit movement until this situation with Coke.”

In response, the American College of Sports Medicine pointed to its stance on licensure, which clarified it applied only to trainers with a certain educational attainment who are working with people who have medical conditions.

Glassman’s campaign against soda does go beyond groups that have challenged his methods. Last year he sent letters to various research groups to ask them to stop accepting money from soda companies.

The American Council on Science and Health, an educational nonprofit, received such a letter because it has received grants from Coca-Cola in the past. Hank Campbell, the group’s president, says the grants had no conditions attached to them and accused Glassman and his supporters of “scaremongering.”

“More awareness is great but demonizing a product is not the solution to America’s obesity problem,” Campbell says.

The CDC Foundation, an independent nonprofit, also received a similar letter from Glassman. Dr. Judith Monroe, the foundation’s president and CEO, responded in a letter that the foundation works to ensure its projects “align with CDC’s mission and priorities, have appropriate research methodologies, maintain CDC’s research independence and do not present any conflict of interest.”