During a local flight, the pilot reported that his engine quit while maneuvering about 1,200 above ground level. The pilot stated that his only option was to land in a soy bean field, and he attempted to fly as slow as possible prior to touchdown. After rolling about 50 feet in the field the airplane nosed over. The pilot reported that for the majority of the 30 minute flight, he was flying with the fuel mixture full rich. He stated that he did not depart with full fuel, and must have been burning fuel at a higher rate than he originally anticipated. According to a Federal Aviation Administration Aviation Safety Inspector, during a postaccident examination the airplane's fuel tanks were empty and no fuel was found at the tank sumps. The pilot stated there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation. The vertical stabilizer and left wing sustained substantial damage.