In preparing for competitive body building, body builders--in addition to continuous and hard muscle training--engage in stringent dietetic manipulations: the first few months of hypercaloric nutrition, rich in proteins, are devoted to the build-up of muscle mass. A second phase of reduced caloric intake is designed reduce subcutaneous fat, while, during the last week of preparations, extreme carbohydrate intake aims at loading muscles with glycogen. Simultaneously, sodium and water restriction results in extracellular and therefore subcutaneous volume deficit and better "definition" of muscle contours and structure. In the course of these dietetic manipulations a young body builder develops hypokalemia, hypophosphatemia, rhabdomyolysis and flaccid tetraparesis. The disturbances are pathophysiologically predictable.