The early church did this, and there are times when I have had nudges to fast about things. I may ignore the nudges, but if they keep coming, I know as well as I am sitting here, that I need to surrender and do what I need to do. Fasting can be several thing, or not having food for a meal a day, or however the Lord leads.
In my older years, I have found that partial fasting is good. In fact it is good to fast something most of the time. I am serious. I don’t always drink tea, Coke, or other things. I usually drink water. It helps with getting in the 6-8 glasses of water per day. Also, I feel better when I haven’t indulged in sweets all day.
I believe God calls people to fast for certain reason. We become sensitive to the Holy Spirit, and it is up to God what we eat, and when to fast. I believe fasting for guidance is wonderful, if you can do this. When I was young I fasting the equal of 3 days. It might be breakfast every day, and then some lunches to get the equivalent of 9 meals fasted. I found that God helped me drop sweets, and bread for one fast time. I believe we live in a world that shows us we need discipline. Fasting is discipline. When God is in it, you will know.