The pilot stated that the airplane's fuel tanks were full prior to departing on the 2.5-hour cross-country flight. Approximately 20 miles north of the destination airport, the pilot observed a low fuel caution. He elected to divert to an airport approximately 20 miles east of the airplane's position, and approximately 2 miles from the diversion airport, the airplane experienced a total loss of engine power. The pilot selected a field and conducted a forced landing. The airplane landed hard resulting in substantial damage to the fuselage and engine firewall. Postaccident examination by a Federal Aviation Administration inspector revealed that the airplane's fuel tanks were void of fuel, and there was no evidence of fuel leakage.