I am toying with the idea of a character who handles time differently.
For them time is slower. To be clear:
They do not perceive time as going slower in the way that one would while waiting for something. Rather time is simply slower for them. You could compare it to the theory in the movie Epic, where smaller things are faster (and so see bigger things as slower).
The character functions, their brain and body can and does keep up with this way of perceiving time.
The obvious consequences are then that they seem very clever. They read faster, reason faster and do faster than other people.
What are the consequences on the body though? Do they age faster and need to eat far more? On a normal (guideline type) human diet would they starve?
I realize that all this largely rests on how much slower time goes for them. For instance if every second for a normal person is two for this character this is not a huge amount of difference. However at one minute for them to the second for us consequences should become large.
Another consequence is that they will probably that everyone seems so stupid (slow!) to that character.
So to sum up: How slow can time go for them while still allowing them to be viable? What are the most important consequences of this blessing (or curse in disguise...)? I am especially interested in the effects on the body rather than the psychology of the character. Anything about psychology in the answer is an extra bonus.