I don’t know how people fast everyday

It’s Ramadan and I don’t know how people fast until sundown each day. I would be so hungry and unable to think straight not to mention really angry. Why does Islam encourage fasting until Eid I think? I believe they eat once a day if I am not mistaken from sundown to sunrise ( reading about it online) . Maha told me she has done it ( fasting) since puberty. She is from Bangladesh and came here when she was very young with her family and her husband’s family is also from Bangladesh which is in South Asia near India and Pakistan and thereabout. What is the purpose of fasting? Genuine question. What is it supposed to do? Any Muslims want to chime in on this question?