 -- Singer Nick Jonas is taking on CrossFit after the company’s tweet about diabetes and an iconic sugary drink.

In a tweet on Monday, the extreme fitness company wrote: “Pour some out for your dead homies.” The comment was posted next to an image of a Coca-Cola bottle and the words “Open Diabetes” and with the hashtags #CrossFit #sugarkills. The tweet was signed by CrossFit CEO Greg Glassman.

The “Jealous” singer responded on Twitter to take Glassman to task, writing: “This is not cool. Please know and understand the difference between type one and type diabetes before making ignorant comments. Sensitivity to all diseases, and proper education on the cause and day to day battle is important.”

Jonas, 22, was diagnosed with Type 1 diabetes at age 13.

Formerly known as juvenile diabetes or insulin-dependent diabetes, Type 1 occurs when the pancreas produces little or no insulin, according to Dr. Jennifer Ashton, ABC News medical contributor and a practicing obstetrician and gynecologist. The cause appears to be unknown, although the body’s immune system mistakenly destroys insulin-producing cells in the pancreas.

In Type 2 diabetes, the body becomes resistant to insulin or the pancreas stops producing enough of the essential hormone. Contributing factors in this form of the disease appear to include being overweight and inactive, also according to Ashton.

CrossFit didn’t appear the least bit chastened by Jonas’ rebuke and by the rebuff from others who joined in to express their displeasure. In fact, the company has continued to tweet about the issue.

It responded to Jonas this way: “Anyone can get T2 diabetes, even those with T1. Stop assuming we don't grasp the difference and help us raise awareness.”

And when another critic wrote: “Not sure @CocaCola appreciates your trademark infringement that insults 29 million U.S. families,” the company responded: “If insulting the sensitive can save some of the 1/3 of Americans who will get T2 diabetes, so be it.”

Glassman, CrossFit's CEO, issued a statement to ABC News in response to Jonas's tweet.

"This is about the scourge of Type 2 diabetes and it's underlying causes. His sponsor, Coca-Cola, is a significant contributor to the diabetes epidemic both with product and 'marketing' spend," the statement read in part.

The rest of Glassman's statement was so aggressive, it was not suitable to print.

Coca-Cola told ABC News that Jonas is not a paid spokesman for the company. A Coca-Cola spokeswoman also responded directly to Glassman, saying that, like him, “we recognize the importance of physical activity and moderation.”

“We promote choice and thoughtful consumption, and through our work with the Alliance for a Healthier Generation we’re working to reduce overall beverage calories,” the spokeswoman told ABC News. “We know these actions will make a real and measurable difference.”

A representative for Jonas also confirms the singer is not affiliated with Coca-Cola.

"Nick has never had a deal or a sponsorship with Coca Cola," Jonas's representative told ABC News. "This is a company desperate for publicity, but it's bizarre that they'd try to achieve it behind such a thoughtless tweet."

Jonas has been an advocate for awareness around type 1 diabetes since his diagnosis and is currently a spokesperson for Dexcom, the glucose monitoring system he uses.

The singer testified about the disease in a 2009 hearing on Capitol Hill.

"It has not been easy but diabetes technology has really helped me be able to manage my diabetes," Jonas told lawmakers.

Ashton, ABC News' medical contributor, says the conversation sparked by CrossFit's tweet is an important one to have.

"I think or hope the intention was to motivate people to live a healthier lifestyle but, in reality, it came out as blaming people who are living with a chronic and potentially very serious illness," she said.