With the on-going war, there probably are tens of thousands of POWs held by the Israeli armed forces. Since Israel had not planned for a war of this intensity, it is likely that the prison conditions are not ideal, including the quality and abundance of food for the inmates. The military does need to keep the inmates fed in order to interview them and collect information from the POWs.
From the videos of the Hamas invaders at the start of the war, it can be seen that many Hamas fighters took time out to loot food. Maybe the prisoners want a different type of food instead of always pita bread.