Most of us when fasting, even the neighbors will know. Fasting is earnestly seeking to be close to God not to get His things. Isaiah 58:4 What good is fasting when you keep on fighting and quarreling? This kind of fasting will never get you anywhere with me.
God sent Prophet Isaiah to warn the Israelites about their practices. They seem to seek God but just as an act. You can full time at church obeying all practice in the physical but be absent spiritually.
In the Bible, after a fast there was results. When we fast, does it bear fruits. Are we fasting or on a diet.