Miracle Dieter Miyuki

Yukimi, a chubby junior high student, discovers a magical dumbbell that can transform her into Miyuki, a beautiful and slender young woman in a revealing costume. But she must do battle with an evil three-star chef who tempts young girls with calorie-rich treats and dubious weight loss products, and keep her identity secret from her family and schoolmates. There is a sequel, "Miracle Dieter Miyuki VV." It is being serialized in Shimbun Akahata. As of Oct 2009, there are no plans to publish it in tankoubon format.