The use of sucrose polyester containing behenate fatty acid chains as a
non-absorbable fat marker to determine total dietary fat absorption by
the digestive tract of a subject. A test food for use in measuring fat
absorption contains a non-absorbable fat and a dietary fat. The method is
useful for diagnostic testing for diagnosing malabsorption of dietary fat
by the digestive tract of the subject, and impairment of dietary fat
digestion in the subject.