She has tried: Kim wrote to Rob during his birthday in March, 'Happy Birthday to my one an.
Rob Kardashian looks even slimmer as he takes Blac Chyna and Tyga's son .
It may be all those healthy meals, or it may be all the running around playing stepdad. Whatever it is that's carving the weight off Rob Kardashian, it certainly seems to be working.
Supportive: Khloe Kardashian, pictured in New York on Wednesday, explained on Good Morning America that she's supporting her brother Rob Kardashian as he commits himself to improving his health