Assume that a species of bigfoot-type animal/person exists. Most of this also applies to ogres or trolls, whatever big dumb giants your particular setting has.
My world's specs:
They range 7-10 feet tall, and are much stronger than humans, and thus require much more food. Their size also causes them to produce more heat, as noted in How to make a realistic 'giant', which could be a problem seeing as they're often covered in enough hair that they don't need clothes.
They are smart enough to use tools, but can't figure out how to make any particularly complex or neat ones. As a rule of thumb (hehe), their tools and structures are made of one or two raw materials you could pick up from the forest floor; dirt huts with branch roofs, log-clubs, leaf-and-fern nests, etc.
They do not have complex language, but grunt at each other like non-human apes.
Basically their intelligence is in a weird middle-ground between sapient and beastly so the characters and audience/readers/players/etc. can debate about it.
I also want mine to be loud and smelly for gross-out factor, but it would give them some have trouble sneaking up on anything.
Here's the bit I can't figure out: How are they even alive? What do they eat that can't outpace them? What sorts of environments would they thrive in?
Assume that they have roughly the same nutritional needs as humans, but scaled up as appropriate for an animal who's about a tonne of dumb muscle. So they probably are omnivorous.