Robert Buchel, a subject on TLC’s “My 600-Lb Life,” died after suffering a heart attack while filming. He was 41.

“TLC was deeply saddened by the loss of Robert,” a spokesperson for the Discovery-owned cable channel told TheWrap via a statement. “We are grateful to his family who were gracious enough to let us continue to share his brave story with our viewers. Our thoughts and prayers are with them at this difficult time.”

Buchel, who weighed as much as 842 pounds, had lost 217 pounds at a Houston hospital in preparation for lymphedema removal surgery. After the surgery, a previously unacknowledged addiction to pain killers led to depression. Buchel stopped exercising and went into cardiac arrest.

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His episode, which aired on Wednesday, included an epilogue with his fiancee recounting their final night together.

“He told me, ‘I don’t think I’ll make it through the night. I love you and I always will,'” she said. “I lost my best friend and the person I was supposed to spend the rest of my life with.”

Buchel is the first “My 600-Lb Life” star to die during filming, though Henry Foots from Season 1 died in 2013 from an illness unrelated to his own weight loss surgery.