The controversial British journalist used his Daily Mail Online column to launch a withering broadside at Lovato, saying the singer had used her platform to "wipe out" the small business.
Lovato went public on social media last week, claiming The Bigg Chill's marketing of "diet" options is "triggering and harmful".
Lovato took to Instagram to call the store out for their positioning of low-fat and low-sugar options near their checkout counters.
"Finding it extremely hard to order froyo from @thebiggchillofficial when you have to walk past tons of sugar free cookies/other diet foods before you get to the counter," Lovato wrote.
"As I read all this patronising, hectoring, stupendously dumb and bullying bilge, I myself began to feel 'triggered'," he wrote.
"The more this repulsively arrogant woman attacked this lovely little store in her staggeringly unhinged and delusional manner, the more furious I became."
"I've seen some revolting celebrity behaviour during the Covid crisis, but little to rival this for sheer nastiness," he added.
As controversy swirled over her statements, Lovato returned to social media to address her critics.
"I am really outspoken about the things that I believe in. I have to remember that sometimes my messaging can lose its meaning when I get emotional," Lovato said in the lengthy video.
"I am human, I am somebody who is very passionate about what I believe in and I've lived through enough to know when to speak up for people who don't have a voice."
Lovato has spoken in the past about her own struggles with disordered eating, revealing she first sought treatment for bulimia at 18 and said that her relationship with food was a contributing factor to her 2018 overdose.
"I didn't control any of my life at that period of time," Lovato recently told CBS.
"Every time I was in a hotel room my phone was taken out of the room so I couldn't order room service."
Demi Lovato took issue with the marketing of the diet yoghurt options. Photo / Getty; 123RF
Admitting that she jumped to conclusions with her initial claims, Lovato stressed in the video that she would be happy to work with The Bigg Chill to "get the messaging right".
Saying she was "protective of the little girl inside me", Lovato said that she would live with her eating disorder for the rest of her life.
"It's really important that everyone understands that my intentions were not to bully a small business, that was not it. I walked in, it was so triggering that I left without froyo and made me really sad."
