On Tuesday night's episode of the new groundbreaking A&E reality TV series "Fit to Fat to Fit," personal trainer Corey packed on 60 pounds in just four months so he could then lose the weight along with his client Raela. In a sneak peek for tonight's episode, Corey realizes that his regular workout routine is a lot more difficult after gaining weight.

Raela is a 31-year-old woman who stands at 5-foot-5 and weighs 253 pounds, and in order to understand her weight loss struggle, Corey agrees to gain weight in order to lose it along with her during their weightloss journey.

"We're about to put Raela through a fitness assessment," Corey tells the cameras in an extended sneak peek. "Let's see what she's got."

The clip cuts to Corey guiding Raela through a series of squats with a medicine ball toss and sit-ups with punches.

"Get this done, get this done," Corey encourages Raela. "Pain don't matter."

"Corey's really intense," Raela says in her on-camera interview. "What the hell did I sign up for?"

"I am curious to see how Corey does with the extra weight but I know it's not going to be easy for him," she says.

In a scene shot four months before his weight gain journey, Corey was able to execute an arm rope training routine with what seems like ease. After his 60-pound weight gain, however, Corey struggles to keep up with that same workout.

"I definitely was embarrassed of my body," Corey says. "I'm more or less a shell of myself."

Corey opens up about the effect his weight gain has on his body in a shorter sneak peek from tonight's episode.

"I got flabby arms, man boobs, this stomach right here is crazy. I mean, look at that," Corey says as he shows off how his body looks after putting on 60 pounds.

"It's a whole lot of weight for anybody, trainer or not," Raela says of Corey's weight gain. "So at least I know he understands where I'm coming from."

Watch a sneak peek from the episode below and be sure to catch tonight's episode of "Fit to Fat to Fit," airing at 10 p.m. on A&E.