There’s actually a pretty good summary at http://en.wikipedia.org/wiki/Jet_lag, which quotes a 2007 Lancet article as “Adjustment to the new time zone is easier for east-to-west travel than west-to-east.” It actually takes me at least a week to adjust either way

Earth rotates from West to East about 1000 mph at the equator, and calculation of your location’s speed has something to do with the cosine, Earth’s orbit speed around the sun of about 67,000 mph, and by the time you’re done with the calculation, the solar system has spun in the Milky Way galaxy, so your answer needs to be adjusted to the handicap as follows:
Equation