Ronnie Ortiz-Magro's Major Body Transformation -- See Pics

A sickness temporarily knocked the 'Jersey Shore' alum out of shape, but he's now back to the gym!

Ronnie Magro's Instagram

Ronnie Ortiz-Magro's known for his burly physique, but his muscles certainly don't come easy, and just like the rest of us, he's got to work to stay in tip-top condition. The former "Jersey Shore" cast member shared photos on Instagram yesterday of some recent weight gain, but, true to form, he's already back in fighting shape. No pain, no gain!

"I really let myself go after I got sick last year," Ronnie wrote with the before/after pics, which chronicle his progress after four weeks back in the gym (were those pesky kidney stones to blame?!). "It's been a long road. I am nowhere I want to be shape wise, but I feel better than I ever did." Hey, feeling good is half the battle -- and Ron, trust us when we say you're still miles ahead of the curve. We snuck three blocks of cheese into a midnight showing of "X-Men" on Monday night and they were gone by the time Magneto emerged from the Pentagon. Suffice it to say, we'll be tucked under a golf umbrella during beach season...

+ Shocked by Ronnie's transformation? Share your thoughts, relive his massive "GTL" routine in the video below and be sure to offer a spot if you see him in the gym!

Photo: Mejia/Asadorian/Splash News