|aOriginally broadcast in 2008 as a segment of: Horizon.
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|aEnglish dialogue
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|a公播版權:科技企業公司
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|aDVD
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|aCamera: Colin Rogal, Mark Langton; online editor: Ben Cull; Film editor: Adam Finch.
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|aNarrator:Peter Capaldi.
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|aExplores the phenomenon of effortless slimness and its biological causes. Investigates genetic factors, evolutionary influences, and learned behavior associated with zero weight gain, as well as the possibility that a virus culd be responsible for some obesity cases. Based on a 1967 experiment involving Vermont State Prison inmates, follows ten volunteers who agree to double their normal intake of calories over four weeks--producing intriguing physiological results.