My religion is Christianity and, according to Christ, His followers are not to make it obvious when they are fasting. He said, "Moreover, when you fast do not look sombre as the hypocrites do, for they disfigure their faces to show men they are fasting. I tell you the truth, they have received their reward in full. But when you fast, put oil on your head and wash your face, so that it will not be obvious to men that you are fasting, but only to your Father, who is unseen, and your Father, who sees what is done in secret, will reward you." Matthew 6:16-18
Yes, there are times when fasting is important, but it should never be broadcast around that you are fasting. That is why any religion that sets aside particular days / months for fasting, and require members to fast, violates what Jesus said. For Christians, it is between them and God alone.