Rob Kardashian is reportedly crushed that his older sisters are not showing him any support with his battle to lose weight. According to a report by Hollywood Life, the 27-year-old feels left out and is upset that Kim Kardashian, Khloe Kardashian and Kourtney Kardashian are not standing by his side.

"Rob feels like no one is on his side - especially Kim, Kourtney and Khloe. He feels like they have turned their backs on him and he's really hurt," the source said. "Khloe was probably his closest confidante but now he's a second fiddle to French Montana. Kim makes him feel like a loser and Kourtney is too busy with her own life to give two hoots about him."

Hollywood Life also claims that Kris Jenner has been pressuring Kardashian to document his weight loss for the new season of "Keeping Up With the Kardashians."

"Kris is pressuring Rob to document his weight loss transition on camera," the source said. "She wants him to make appearances on the new season of 'Keeping Up With the Kardashians.' Rob is not into the idea at all and just wants to stay out of the spotlight."

Recently his trainer, Gunnar Peterson, spoke to People magazine about the reality star's fitness regime and how he plans on helping Kardashian drop the pounds. Reportedly, before Kardashian left Paris and bailed on his sister's wedding, he sent a text to Peterson and asked the celebrity trainer to help him get in shape.

"I think Rob knows exactly what to do. He's worked out [before] and he's focused," Peterson said. "We're doing intervals with strength movements: squats, the sled, swings and push presses. It's about getting his heart rate up and keeping it up."

Peterson said he's not trying to get Kardashian down to a certain weight but wants him to be able to look in the mirror and love what he sees.

"I don't have a scale, I'm not big on measurements. Until a person looks in the mirror and is happy with themselves, you have not reached your fitness goals," Peterson told the magazine.

"They key to anyone's success is staying with it," he added.

Even though Kardashian has a busy schedule, Peterson said the 27-year-old has been making time for his workouts.