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Love is still doing wonders for Rob Kardashian's health.

The newly-minted 29-year-old looked slimmer than he has in years when he stepped out for a little shopping on March 23 with his girlfriend, Blac Chyna's son, King Cairo.

Pushing a full shopping cart through the parking lot of a Toys 'R' Us in Calabasas, Calif., Rob's white outfit choice of a T-shirt and shorts did little to hide his increasingly fit figure -- a major step forward after a long stretch in which he opted for super baggy sweats the few times he allowed himself to be seen in public.

Rob has reportedly lost more than 50 pounds in recent months, thanks in part to his controversial relationship with Blac Chyna. He's also been using social media more, suggesting his social anxiety and depression are under control these days.

"The whole family sees that it's [Blac Chyna] who brought Rob back," a source recently told Us Weekly. "Kris is so grateful to Blac Chyna for rehabilitating her son."

It's been a bumpy road for the family since Rob and Blac Chyna started dating in January. Khloe Kardashian reportedly kicked Rob out of her house after finding evidence that the couple may have been partying there while she was away.

And Rob's half-sister, Kylie Jenner, wasn't thrilled about the idea of her brother dating the mother of her boyfriend, Tyga's child.

But it's hard to deny Rob's physical and emotional transformation during the course of his new relationship.

Judging from recent photos, King Cairo seems to be happy with the new setup, too. Rob joined the smiley-faced 3-year-old and his mom for some fun at Legoland and at a playground last week.

Blac Chyna and Rob both documented the pseudo-family's sunshine-filled day, with Rob captioning one of the couple's sweet pics, "Pre Birthday Turn up."

The next day, his whole family chimed in on social media to wish him a happy 29th.

"Happy birthday to my sweet brother! My best friend! My ace forever!!!," gushed Khloe, putting aside any Blac Chyna-related differences she and her brother may still have.

"My love for your knows no bounds. You are and always will be my ultimate and all I ever wish for you on this day and everyday is your true and complete happiness."