Protein sack

Given the fact that humans eat a lot of protein, and aside of water and bone, are predominantly protein. We can end up with a conclusion that "protein" is what makes up the first part of this definition.

A sack is a sort of flexible, strong, bag like, and sometimes natural biological container to hold everything from burglars swag, random items, rubble, to biological organs, through to general waste. Considered a low key, low cost storage item and generally disposable.

When you are talking of many humans, It is fair they can be referred to as protein sacks. This is considered a form of insult towards humans of low or inept value.

FACT : Calling someone a sack of shit would be too offensive in some situations, so you can call them a protein sack INSTEAD. Shit is also made of protein amongst other things, and is the defecated waste that is produced from a living thing.