The singer shared a screengrab of the ad on her Instagram story, showing one slim cartoon girl with the label “pretty” and another heavier animated girl with the label “obese”.
“Why is this fat-shaming bullshit on my feed?” she asked. “So many things wrong with this ad. You can be ‘pretty’ at any weight.”
She then showed a second screengrab where the heavier girl’s label had been changed to “controlled”, with sprigs of broccoli underneath her.
Demi continued: “This is absolutely harmful to anyone who is easily influenced by societal pressures put on us from the diet culture to be constantly losing weight in a world to equate our value with the way we look and especially anyone in recovery from an eating disorder. Especially when eating disorders are all about ‘control’.
“So please Instagram, keep this bullshit off mine and other’s feeds who could be easily [affected] by this disgusting advertisement.”
She added: “With how aware people are becoming of mental health and mental illnesses, I expect you guys to know better [than] allowing this advertisement to be allowed on your app.”
HuffPost UK has contacted Instagram for comment, and is awaiting a response.
In the past, Demi has spoken candidly about her own history with eating disorders, which the former Disney star – who has also struggled with depression, self-harm and substance abuse issues – described in 2017 as “the biggest challenge in her life”.
Last year, Demi was hospitalised for two weeks and entered an in-patient rehab facility after suffering a drug overdose, describing herself at the end of 2018 as “sober and grateful to be alive”.
Useful websites and helplines: