Khloe K. champions Rob Kardashian's "fat boy" diet

Feb 22, 2013 at 1:55 p.m. ET

Rob Kardashian's weight-loss plans mean lots of healthy eating and many miles to run. Luckily, the reality star has sister Khloe Kardashian to cheer him on, even when his choice of words leans towards self-deprecation!

Rob Kardashian

Rob Kardashian's breakup with Rita Ora was not only hard emotionally, it took a toll on both his wallet and waistline!

Opening up about his behavior after their relationship ended in December, Rob Kardashian admitted on an episode of Kourtney & Kim Take Miami, "All I did was waste a lot of money and gain 40 pounds. I need to focus on me. That’s all I wanna be about."

The 25-year-old, who had only confirmed he and Rita Ora were an item two months before their gossip-worthy breakup, was advised by sister Khloe Kardashian, "The best form of revenge is a good body!"

Rob Kardashian says Twitter rant wasn't about Rita Ora >>

Proving she's got Rob's back, Mrs. Odom tweeted Feb. 20, "I have the best brother in the world."

The following day Khloe's cheerleading continued after her little bro shared an Instagram photo of what appears to be pink grapefruit and an omelet with the caption, "Another fat boy breakfast. Let's go! 5 mile run next. 50 pounds gots to go!"

Wasn't that 40 pounds earlier? Way to set your sights high, Rob!

Retweeting his message, Khloe Kardashian kindly added these four ego-boosting words: "I believe in YOU."

Khloe Kardashian says curves give her confidence >>

This isn't the first time Rob Kardashian's weight has been a topic of conversation. During his 2011 spin on Dancing with the Stars his partner, Cheryl Burke, shared of his body taking shape, "He's lost a lot of weight. His whole physical appearance has changed. He's using different muscles. He's super-sore all the time."

She continued, "I can tell Rob is getting more comfortable with his body because he's starting to wear tank tops to rehearsals. And you'll see his arms out. In the beginning, you'd never see that. He looks at himself in the mirror. It's really cute."

With hard work and sister Khloe's encouragement, Rob Kardashian will hopefully once again look and feel like a dashing Kardashian!

Image via WENN