Check out the video ... Chyna scoffs at the food choices, including fat free sorbet, I Can't Believe It's Not Butter, wheat tortillas, oatmeal and quinoa. BTW ... there's also pizza crust mix, although it's wheat.
TMZ broke the story ... Kris helped Rob buy a house in the Calabasas community where his sisters live. It seems Chyna's none too happy his family is back in the picture.
Our Kardashian sources tell us they think it's despicable Chyna's making fun of Rob's family for trying to help him beat his diabetes and weight issues.
To Chyna's credit, Rob has lost around 40 lbs on her watch.
Rob made it clear which sides he's picking between Chyna and his fam with a very descripitive IG post late Tuesday night ...