LOS ANGELES • Reality television star Kim Kardashian called out those who bully and body-shame others, recalling her embarrassment when she was attacked for gaining 27kg during her first pregnancy.

In an Instagram Story last Friday, she detailed how she had been compared to a killer whale during the later stages of her pregnancy in 2013, and how her figure was contrasted unfavourably with Kate, wife of Britain's Prince William. The Duchess of Cambridge was also pregnant at the time.

"I cried every single day over what was happening to my body, mainly from the pressures of being constantly compared to what society considered a healthy person should look like - as well as being compared to Shamu the Whale by the media," the 40-year-old reality star wrote, referring to the mammal that used to perform at SeaWorld.

"I was shamed on a weekly basis with cover stories that made my insecurities so painful, I couldn't leave the house for months after. It really broke me," said Kardashian, who rose to fame through her family's reality TV show, Keeping Up With The Kardashians (2007 to present).

The cosmetics businesswoman and social media star said she was reminded of those months while watching a recent documentary about American singer Britney Spears, tracing the meteoric rise of the pop star and the media coverage of her mental health breakdown in 2007.

Kardashian said the documentary made her empathise with Spears. She said the media "can be very traumatising and it can really break even the strongest person".

"No one deserves to be treated with such cruelty or judgment for entertainment," she told her 208 million Instagram followers.

Kardashian gave birth to her daughter North in June 2013. She went on to have a son, Saint, in 2015 and later had two children by a surrogate because of health complications.

Last month, she filed for divorce from rapper Kanye West, her husband of almost seven years.

REUTERS