Mama Cass is before my time, but I find this stuff fascinating.
From Wiki:
"At the height of her solo career in 1974, Cass Elliot performed two sold-out concerts at the London Palladium. She telephoned Michelle Phillips after the final concert, utterly elated that she had received standing ovations each night. She then retired for the evening, and died in her sleep of a heart attack. Standing 5 feet, 5 inches tall, she had weighed as much as 300 pounds since high school. The excess weight combined with numerous attempts to reduce her size with extreme crash dieting put a great strain on her heart, until it finally gave out."
It also says that she was married to Jimi Hendricks for a very short while so he could avoid being drafted.