The Day of Atonement is the one day in the Jewish calendar that has no other historic or seasonal connotations: Yom Kippur is about asking God for forgiveness. A Jewish person spends the first nine days of repentance making things right with others, then on the tenth day, Yom Kippur, they are free to ask for and receive forgiveness from God.
During the Yom Kippur holiday there are five services of worship. It is also a day of fasting for Jewish people who have reached religious adulthood (girls over 12 and boys over 13 years of age). A complete fast lasting some 25 hours is not a physical punishment. Rather, the fasting allows the believer to fully concentrate on their relationship to God, knowing that their focus need not be interrupted, not even for a meal. We are like angels during that day and as we know, angels are not connected to the physical needs of the world.