Millions of people do this during Lent as a sign of sacrifice and to test their self-discipline.
Christians believe that this is to represent Christ’s sacrifice when he went into the desert to pray and fast for 40 days before later dying on the cross.
In The New Testament, while Christ was there, Satan tempted him to turn away from His earthly mission and purpose to worship him instead. Christ refused, which is why people may give something up, in order to test their self-discipline.
Could you give up something you “truly” enjoy for the next 28 days, to prove you are disciplined?