Restoration does not require the return of every temporary nutritional addition. The original identity-bearing parts of a person can be assigned to that person, whereas material taken in as food by another may be an acquired or additional part of the latter's body.
The same particle need not therefore be placed simultaneously in two bodies. The distinction supplies a response to the supposed double claim over a component.
This is a solution within a particular classical theological account; it is not a scientific inventory of the microscopic material making up a human body.