December 2, 1923 - September 16, 1977: Age 53
One of the greatest opera singers of the 20th century, Maria Callas grew up in America but spent her youth in Greece. She had an unusual voice and a very strong personality, and experienced great success during the 50s and early 60s. Naturally a heavy woman, Callas undertook to lose 80 pounds in 1953-54, and her resulting slim, graceful figure ensured her status as a superstar outside of the opera world as well as within it. It was rumoured that she had lost the weight by use of a tapeworm, but there’s no evidence to support that, and she herself said she lost it through a judicious diet of chicken and salad greens.
It is possible the the large loss of weight led to vocal problems. When the body changes radically, the singer must compensate; because of Callas’ high profile, any difficulties, real or imagined, were made much of in the press. That, combined with personality clashes and accusations (not always justified) of difficult behaviour, led to the decline of her singing career. She lost confidence, and her vocal problems increased. Her last public performance was in 1974 and was described as “an artistic failure”.
She spent her final years a virtual recluse in Paris. On September 16, 1977 she doed, ostensible of heart failure, but there were rumours that her assistant murdered her in order to gain control of her considerable estate (she had no children). Nothing was ever proven, and the assistant did benefit greatly from her death (he was in her will and already had control of her estate before she died). However the accusation of murder was never taken seriously. It is likely that her heart failure was precipitated by overuse of sleeping aids.
Sources: Wikipedia, The Maria Callas Official Web Site