Kim and Khloe Kardashian’s have both been bullied for their weight, but that isn’t stopping them from weighing in on their brother Rob’s body image!

In a preview clip from this Sunday’s episode of E!'s Keeping Up with the Kardashians, the famed sisters get snarky about their younger brother’s sudden weight gain, making jokes about his stretch marks and strategizing how they are going to trick him into quitting his fast food habit – and Breaking Celebrity News has the video.

While having lunch together at Kim’s home, the sister chat about the aftermath of Rob packing on over 40 pounds in the wake of his breakup from Rita Ora.

"So I was getting a massage last night, and the girl told me if you scratch yourself that's how you get stretch marks because your skin gets really itchy,” Kim, who has been dealing with weight bullying herself during her pregnancy, says to Khloe. “And Rob has them. Maybe for the fact that he flakes on me all the time.”