STARPICZ/Splash News Online
03/16/2013 at 10:25 AM EDT
After revealing on social media
that he's put on weight over the last year, Rob Kardashian has been working hard to shed the pounds.
"I'm trying to lose 40," the Keeping Up with the Kardashians
star told PEOPLE at his birthday party Friday at 1 OAK Las Vegas. "It's a little journey."
Kardashian, who turned 26 on Sunday, said he works out twice a day – in the morning with a trainer and later with his friends.
Calling his recent 240 lb. weight his starting point, he dropped 5 lbs. last week and wants to get down to 200 lbs. by the Fourth of July.
Though Kardashian says "good eating" is what expanded his waistline, he reportedly put on the weight following his breakup with singer Rita Ora and when he stopped performing on Dancing with the Stars
at the end of 2011.
Aside from his group of about 30 friends he works out with, Kardashian has someone else in his corner: former Dancing
partner Cheryl Burke.
"We've been running and doing our own little things and it's good," he says.