No small feat! Rob Kardashian has lost approximately 50 pounds since beginning his weight loss journey in 2018, Dr. Niket Sonpal exclusively tells Life & StyleWhile the New York City-based internist and gastroenterologist has never personally treated the former Keeping Up With the Kardashians star, Dr. Sonpal estimates Rob, who started off around 300 pounds, now weighs about 250. “It looks like he’s on a path to better health.”

The Arthur George founder, 33, debuted his slimmer build at Khloé Kardashian’s 36th birthday party on Sunday, June 28. Rob was all smiles as he posed for rare photos with the rest of his famous family — including Khloé’s ex Tristan Thompson and Kourtney Kardashian’s ex Scott Disick

“The Kardashians are proud of Rob for losing so much weight,” a source exclusively reveals to Life & Style“More than anything, they’re relieved that he’s taking better care of himself.”

In the past, when Rob was “feeling down” he would “isolate from the rest of the world and spend days on end eating junk food, watching TV and playing video games.” However, “he seems to have snapped out of it,” the insider assures. “They hope he keeps up the good work.”

When it comes to Rob’s health and fitness routine, he’s been working closely with “personal trainers” Khloé and Tristan, says the source. The Good American founder went through a weight loss transformation of her own and Tristan, 29, is a professional athlete. The trio uses Khloé’s home gym for “cardio, running, push ups and deadlifting.”

Diet-wise, Rob has “cut out the junk food” and eats “high-protein” meals with a few “cheat days” every now and again, the insider explains. As a result, he’s “regained his confidence,” has “more energy” and is “feeling healthier than ever.”

When Rob isn’t breaking a sweat with his sister and her former flame, he’s spending time with his daughter, Dream Kardashian, whom he shares with ex Blac Chyna. In fact, a separate source previously told Life & Style “running after” Dream, 3, is “the easiest and most fulfilling workout.”

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