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Kirstie Alley

One of the most notorious yo-yo dieters, actress Kirstie Alley, 60, was once the face of Jenny Craig. She lost 75 pounds with the diet plan’s help, but gained much of it back after her contract ended.

She starred in her own show about her struggle with her weight in the mid-2000s, when her weight had ballooned to over 200. In 2008, she pledged to lose 80 pounds, and tweeted in September 2010 that she had just 30 more to go.

Next: Ricki Lake