IDK.  I hear "this is all muscle" from fat dudes all the time.  Fat men don't even seem to know that they are fat.  The delusion is actually stronger in them.  Fat women absolutely do know they're fat which is why they make so much noise about it.  The lady doth protest too much.  Fat men are the ones who pretend it isn't happening and continue to shovel fried food and beer down their gullets.