Stephen Furst, known for his scene-stealing turn as Flounder in National Lampoon’s Animal House, died Friday.
The actor passed away at his California home from complications due to diabetes, his sons confirmed on Facebook. He was 63.
Born in Norfolk, Virgina, the late actor had a life-long history with the disease. He lost both his mother and father to complications from diabetes when he was just 16 years old. Within weeks of each other, Furst’s father and mother died from heart disease and leukemia, respectively.
Furst would later discover he also had diabetes weeks after his father’s death but didn’t take the diagnosis seriously. “I went into denial,” Furst previously told Diabetic Living. “I didn’t realize the long-term effects.”
Ignoring his illness, the actor went on to live his life, marrying his college girlfriend Lorraine Wright before they both set out to Los Angeles so Furst could pursue acting. He later landed the role as the lovable frat boy Flounder in the hit Animal House and starred on NBC’s St. Elsewhere for five seasons.
But an accident when he was 40 led to a major lifestyle change. After ignoring a blister on his foot that developed a threatening infection, Furst was at risk of losing his leg when he finally sought treatment. “The doctors told me that amputation might be the only way to stop the spreading infection,” he told USA Today in 2001.
Even when facing the possibility of amputation, Furst still wasn’t taking his diagnosis seriously and tried sneaking in a large order of Chinese food. When the hospital staff confiscated the food and instead put him on a diet plan, Furst quickly lost weight — and realized he could make a significant change.
“Like most severely overweight people, I had to hit a rock-hard bottom before I’d take responsibility for the consequences of neglecting my own health,” he admitted to the outlet.
The actor lost over 100 lbs. and became an advocate for the prevention of diabetes.
“The way to deal with the devil of obesity and diabetes is literally one day at a time,” Furst said. “When I achieved my weight goal, I bought myself a bracelet inscribed with the following 12-Step prayer: ‘God grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference.’ The magic is you can change more things than you could ever dream of.”
After his death, his sons, Nathan and Griffith, took to his Facebook page to honor their father.
“If you knew him personally, remember his gift for lighting up a room,” they wrote. “And no matter who you are, when you think of Steve, instead of being sad, celebrate his life by watching one of his movies or use one of his bits to make someone else laugh — really, really hard.”
This article originally appeared on PEOPLE.