Simplify the following text for a Grade 9 native English-speaking person.
Original: The term `` fiber '' is something of a misnomer , since many types of so-called dietary fiber are not fibers at all .
Simplified: Dietary fiber includes substances like cellulose , wax and lignin , among others . The term `` fiber '' is not the best way to describe it , because many of these substances are not actually fibers .