What if one takes an oath not to eat, and then ingests non-food items, does that break the oath? What about eating non-kosher food? The key is the "isur kolel," an inclusive prohibition. For example, not eating on Yom Kippur is more inclusive than not eating non-kosher food. Also, more extensive prohibitions -- prohibited in the kind of food and the circumstances of eating (for example, consecrated, or Yom Kippur). In one scenario, multiple things can be forbidden at the same time, each nested within the other, as it were.