On last night’s episode of Keeping Up With The Kardashians, three of the five sisters opened up about the body parts that make them feel the most self-conscious.

“When you are photographed all the time, it’s natural to have insecurities,” Khloé explained during the opening scene in a dermatologist’s office, where she had stretch marks zapped off her behind—while Kendall and Kim snacked on pastries in the exam room, natch.

Kylie Jenner, the youngest at 17, admitted to getting temporary lip fillers, finally answering months of speculation about her suddenly plump pucker. "It's just an insecurity of mine, and it's what I wanted to do," she said.

RELATED: 17 Surprising Reasons You're Stressed Out

But 19-year-old Kendall Jenner surprised us with her refreshing take. As she chatted with Kim and Khloé about Kylie's lip injections, Kendall said she didn’t see the point: “[Kylie’s] a beautiful girl. I don’t think she needs anything.

Later, in a heart-to-heart with both of the younger girls, Kim encouraged Kylie to come clean with the media about her fillers. The teen has been avoiding the question for months. “If they ask about your lips, own up to it,” Kim urged.

“I don’t know why you guys are even freaking out, or talking about this though,” Kendall interrupted. “No one needs anything—everybody’s beautiful.”

But Kim insisted that if something makes you insecure, it’s natural to want to fix it. She confessed that she’s so worried about her weight lately (“I’m legit 20 pounds heavier”), she can’t leave the house without Spanx.

“You do realize who you are, right?” Kendall piped up with another dose of reality. And she didn’t stop there. Kendall kept pushing, trying to get Kim to recognize how gorgeous she is—just as she is. Turns out, Kendall is a model sister on top of being the face of Estée Lauder.

RELATED: Best and Worst Celebrity Health Habits