I just read a review of a book that mentions how one's ethnicity plays a
part in how many carbs a person needs.  Basically, northern europeans from
cold climates need very few carbs, mediterraneans need a moderate amount,
and those from tropical climates may need an abundance.  I have found that
many fruits and even bananas agree with me - maybe this is because I am
half Italian.  My mothers side is mixed with Russian so this complicates
things.  However, my blood type is O (so are my Mediterranean relatives)
and this is supposed to be a pretty carb intolerant group according to
another theorist.