Fat and Thin (1985)

An imposter and thief called Dumpling escapes prison and arrives to a respectable institute of doctor Strukl in Balm Sanatorium. The doctor is a specialist for reduction and gaining of weight, and wanted by many celebrities, especially because it is known that he has specialized in Switzerland. Dumpling, discovering that he is physically similar to doctor, and seeing his big chance in it, disables the doctor and takes his place at the sanatorium.