Fasting

I'm ashamed to admit that I'm not very good at fasting.  I'm reading "Spiritual Classics" by Richard Foster and ran across a section by Catherine Marshall.  She wrote about fasting from criticizing.  She mentioned how hard it was to be silent and not criticize anyone or anything for a 24 hour period. 

As I thought about it, I started to realize that I can be very, very critical.  I really felt the challenge of doing a 24 hour fast from criticizing - from both saying and thinking critical, harmful thoughts.  I made the commitment and not five minutes later I found myself in a situation where all I wanted to do was complain and find fault with a person who didn't do what I thought they should have done.  But the good thing was that I felt really convicted.  I'm still in that 24 hour window.  I'm trying to think carefully before I speak, and I'm asking God to help me keep from a critical mindset.  I want to break the pattern. 

Anyone else out there struggle with this?