The biblical definition of fasting is that it’s a christian’s voluntary abstinence from food for spiritual reasons. In the bible fasting was always with food but if you can’t fast food for some reason, maybe you’re diabetic or pregnant, or you really feel lead to fast something else that you think takes your attention away from God like TV or social media, then you can fast that but there is something about food that REALLY effects us physically.
All through the Bible it’s very clear that doing something in the physical is a catalyst to seeing breakthrough in the spiritual. What we do in the physical gets the attention of heaven and mobilises the angel armies like when the Israelites fled from Egypt in Exodus 14. When they reached the Red Sea, God told Moses to lift up his staff and stretch out his hand. His OBEDIENCE to do the physical action resulted in a supernatural miracle.
Here are three things that fasting is not and six things that fasting is. This is not a comprehensive list but things I hope can help us for now.