Eminem's prescription drug addiction left a hole in his stomach.
The Real Slim Shady rapper saw his weight balloon to 230lbs at the height of his problems, and attributes the gain to trying to relieve stomach ache brought on by the discomfort caused by drugs such as Vicodin and Valium.
He said: "In 2007, I overdosed on pills, and I went into the hospital. I was close to 230 pounds. I'm not sure how I got so big, but I have ideas.
"The coating on the Vicodin and the Valium I'd been taking for years leaves a hole in your stomach, so to avoid a stomachache, I was constantly eating - and eating badly."
After leaving rehab, the 42-year-old star was determined to tackle his problems by exercising, but quickly found himself with a new addiction, to running.
Writing in the September issue of Men's Journal magazine, he added: "When I got out of rehab, I needed to lose weight, but I also needed to figure out a way to function sober.