[wruza]

The past traveler (P) had some atoms. Then he turns into future self (F) by eating, breathing and other human activities. F != P wrt atomical identity, but intersect(F, P) is a non-empty set. If we use that time machine to return everything except F into 2010’s place, P himself will lack some crucial matter. And so will other random objects that were not-P back then.

There’s no need for transplant to make the idea absurd^W troublesome.

Edit: But the answer is still good.