Have people ever really eaten tapeworms for weight loss?

Opera singer Maria Callas was rumored to have used a tapeworm to achieve a remarkable loss of weight in the mid 1950s. She did, in fact, lose more than 60 pounds over several months. She was also known to have contracted a tapeworm at some point in her life. However, the two incidents are probably unconnected. Callas enjoyed rare steak, so she probably got her tapeworm accidentally. These two aspects of her life were jumbled into a persistent rumor.

There is evidence of advertising, from the late 19th and early 20th century, hawking "sanitized tapeworms" to help women maintain a slim figure. Whether the pills sold actually contained tapeworms or whether women actually ingested them hoping to acquire a tapeworm is difficult to verify. Such a pill would likely contain the cyst part of the tapeworm's lifecycle, but one would imagine that cultivating a large supply of these would make for a rather unpleasant day's work. It seems unlikely, but there's also a good chance that somewhere in the long, strange history of humanity, someone somewhere did try using a tapeworm to lose weight.