In Islam, we respect the peace of a soul, which is why we read Quran all year as much as possible for the death anniversary when number of "paras"(Quran is divided into 30 books) are to offered by an "Hafiz" to that loved one's soul.
This is so that soul gets peace and is remembered, if on these auspicious days when souls are released to visit their houses but no one does any ritual, the souls leaves wailing and upset.
It is called "Khatam" my parents and relatives always do it every Thurday, very simple ritual, my dad does "wudu" (pronounced wuzu) to be paak(clean) then my mum makes a delicious dish, put fruit, water, dish on the table and my dad reads du'a over. That food then must not be wasted.
It is just a way of doing it properly.
Food: Maybe it is like "Prashad" (sweets) that hindus eat at the end of Puja or bread on Sunday community service.
I think this is something very important and just great to do with respect, if we really care or love our passed ones. Word to describe will be that- it is "meaningful" to do.
"Hazrat Abdullah ibn Abbas (radi Allahu anhu) has stated: "On the Days of Eid, the 10th of Muharram, the first Friday of Rajab, on Shab-e-baraat (15th Sha'ban) and on Thursday nights, the souls of the deceased are left free to go to their homes, wherein they go and ask for Sadaqa and Khayraat. If they do not receive any Du'a or Fateha, then they return to their graves saddened and disappointed and they say, 'O Allah! They have deprived us, You deprive them".