Kim Kardashian's swimsuit selfie was a "big middle finger" to everyone who called her fat.
The reality star, who gave birth to daughter North West four months ago, said she wanted to hit back at those who had criticised her weight gain while she was pregnant.
Appearing on 'Tonight with Jay Leno' on Wednesday (30.10.13), she said: "I actually just sent that [picture] to my boyfriend, my fiancé, and I was like, 'Babe, can I post this up? This is my big middle finger to the world on (sic) everyone that called me fat.' "
Kim, who got engaged to rapper boyfriend Kanye West on her 33rd birthday earlier this month, has now lost 3st 6lbs after going on the Atkins diet.
She said: "It was the hardest challenge of my life but I was dedicated and motivated.
"It's a newer version now [Atkins] and I really researched it.
"At the beginning I couldn't exercise a whole lot but then I just started going on hikes with different family members and my boyfriend and it worked."
The 'Keeping Up With The Kardashians' star said the negative publicity about her weight was difficult to deal with.
Kim said: "It really did affect me... It really hurt my soul. It changed how I am, I think, in the public a little bit.
"I was gaining weight because I was pregnant. It was just really hard to read all these stories and hear all these nasty things."
She said she wasn't in "hiding" after giving birth, but "adjusting her life".
Kim added: "Why would I subject myself to so much negativity, especially now I have a daughter?"