Good stepdad! Rob Kardashian takes his girlfriend Blac Chyna's son King Cairo toy shopping

Rob is really looking good and skinning! It may be all those healthy meals, or it may be all the running around playing stepdad.  Rob Kardashian cut a much slimmer frame as he took his girlfriend Blac Chyna and Tyga's son King Cairo toy shopping on Wednesday. Photos after the cut.

The 29-year-old's ever-slimming frame was clearly in evidence during a shopping trip on Wednesday. Whatever it is that's carving the weight off Rob Kardashian, it certainly seems to be working.

The sock mogul was taking his girlfriend Blac Chyna's son King Cairo on a bumper store run to Toys 'R Us in Calabasas.

Rob has reportedly lost more than 50lbs since his return from his self-imposed media exile on the arm of his sisters' nemesis.

And although he isn't yet back to the peak physical shape he enjoyed in his early 20s, he is certainly getting there, thanks to Chyna's healthier eating and exercise regime.