07/10/2011 at 11:30 AM EDT
It was one night a year ago when he was lying in his bed, all 365 lbs. of him, when Corey "Big Hoss" Harrison realized his weight was out of control.
"I was watching this lawyer's commercial and it was talking about the side effects of this drug, and I was on that medication because of my weight," the star of the hit History Channel show Pawn Stars tells PEOPLE. "I went and got a Lap-Band put in and the weight just started falling off. It was like someone took a backpack full of rocks off of you."
Due to the Lap-Band, coupled with a protein-heavy diet and strenuous workouts with a trainer five days a week (a gym was built in his Las Vegas pawn shop), Harrison lost 115 lbs. over the past year, down to about 250 lbs.
"I changed my diet huge," he says. "I start out with a protein shake or Power Bar. I probably have five protein shakes a day. At dinner, I usually go off the chain a little bit and have whatever I want but within reason. I think maximum capacity for my stomach is about 6 oz. of food."
With his weight more under control, Harrison is off all his medications and it no longer considered a prime candidate to be diabetic, which he once was.
"I wake up in the morning and I'm not tired all day," he says. "I have more good days than bad days. My knees don't hurt. My hips don't hurt. My back doesn't hurt. I can run now. I have family that are diabetic and I've seen the hell it's put them through and I've told myself, I'm not going down like that."