Bigorexia

Muscle dysmorphia is a subtype of the obsessive mental disorder body dysmorphic disorder, but is often also grouped with eating disorders. In muscle dysmorphia, which is sometimes called "bigorexia", "megarexia", or "reverse anorexia", the delusional or exaggerated belief is that one's own body is too small, too skinny, insufficiently muscular, or insufficiently lean, although in most cases, the individual's build is normal or even exceptionally large and muscular already.