Because injera itself never changes between a fasting day and an ordinary one, the visible marker of a fasting meal in an Ethiopian or Eritrean Orthodox household is almost entirely in what sits on top of the bread rather than in the bread underneath it: the same round of injera, torn by hand and used to scoop up whatever stew is served, might carry a rich meat and butter based wat on a feast day and a vegetable based fasting wat the next, without the base of the meal changing at all. That constancy has a practical side, since a household does not need two different staple foods for its two different modes of eating, and a spiritual one, since it keeps the fast focused on what is added or withheld rather than on the shared act of eating together from a common plate, which is not itself suspended during a fast.
Ethiopian and Eritrean Orthodox Christians who keep the fasting calendar closely will describe entire weeks and months of the year as fasting periods, and restaurants and households alike in these communities commonly prepare a specifically fasting, tsom, menu built around lentils, split peas, chickpeas and vegetables during those stretches, still served the same way, over the same injera, that any other meal would be.