This sure is much ado about nothing. If you go to bed at different times each night, get up at different times in the morning, do a lot of travelling between time zones, eat your meals at different times depending on your situation that day, your body can handle the time change just fine.

It's those who have rigid schedules and always do things at exactly the same times every day that will have a problem.

The first group will have bodies used to changes---the second group won't, so any change will mess them up.