Jesus spoke about it. He went as far as to say that God will reward you of you do it. “And when you fast, do not look gloomy like the hypocrites, for they disfigure their faces that their fasting may be seen by others. Truly, I say to you, they have received their reward. But when you fast, anoint your head and wash your face, that your fasting may not be seen by others but by your Father who is in secret. And your Father who sees in secret will reward you” (Matthew 6:16-18)
Notice, Jesus says when you fast-- not if you fast. He’s assuming that people will fast. He believed that His church would fast. In the book of Joel, God says to return to Him with fasting and weeping. This kind of fast was done as a way to mourn. If you are diabetic, I would recommend talking to a doctor before fasting (just to make sure that it is safe to fast).
For me personally, God has had me fast and pray for people. Fasting is a way to yearn for closeness to God. It’s devotion with a passion. Prayer and fasting go together like chocolate and peanut butter. When you are praying and fasting with such a passion that food and drink almost become an immorality, God becomes closer to you. It’s a way to seek closeness to God, so I would recommend fasting to anyone, except in the case of where someone has a health condition that prevents them.