Sofie Hagen, a comedian based in London, lost her cool on Twitter this week over a cancer research organization’s ad that highlighted the link between cancer and obesity.

The advertisement, from the medical research organization Cancer Research UK, highlighted the link between cancer and obesity. “OB_S__Y is a cause of cancer,” the ad read. The organization was referencing a number of studies that showed that obesity can lead to a number of cancers as well as other issues.

“Right, is anyone currently working on getting this piece of shit CancerResearchUK advert removed from everywhere? Is there something I can sign? How the fucking fuck is this okay?” Hagen wrote.

“What your campaign is doing is so incredibly damaging, that I can’t even begin to describe it in only 280 characters. There are many people who have tweeted me their articles about it, try reading those. There is no excuse for you to have this campaign up,” Hagen added in a follow-up tweet.

“And you can absolutely go away in terms of trying to excuse it. Society viewing fatness as a negative thing is a thing that kills more than the cancer that you MIGHT get due to MAYBE something to do with you POSSIBLY weighing MORE than a CERTAIN weight POSSIBLY MAYBE,” she continued.

Hagen finished her rant by arguing that dieting is the worst thing a human can do to their body. “DIETING has been proved TIME AND TIME again to be one of the worst thing you can do to your body. Your campaign is so damaging and fatshaming and I really hope it gets taken down,” she said.

The organization responded directly to Hagen’s tweet. “After smoking, obesity is the second biggest cause [of cancer]. It is our duty to inform people about this and lobby the government on policies which will help us all to keep a healthy weight,” they wrote.

On Friday, Hagen was still tweeting about her exchange with the cancer research organization. Hagen said that she refuses to believe that obesity can lead to health issues such as cancer. “…I am not buying into fat being unhealthy – it’s not inherently unhealthy and even if it was, fat people can do whatever the fuck they want with their health – but if I did pretend to accept that, your arguments are still fucked up,” she wrote.

Just this week, Johns Hopkins University hosted a guest speaker who argued that humans can be healthy at literately any body weight.