Just cast it (int)enumVal:

enum BodyType
{
  Fat,
  Thin,
  Musclebound = 500,
  Anorexic
} ;

class Program
{
  static void Main( string[] args )
  {
    BodyType debbie = BodyType.Fat ;
    BodyType john = BodyType.Anorexic ;
    BodyType harold = BodyType.Thin ;

    Console.WriteLine( "Debbie is " + debbie + ".  Numerical value: " + (int)debbie ) ;
    Console.WriteLine( "john is " + john + ".  Numerical value: " + (int)john ) ;
    Console.WriteLine( "harold is " + harold + ".  Numerical value: " + (int)harold ) ;
  }
}