Fasting where I give up meat during certain sacred Hindu festivals. My longest was 41 days. I also tried observing celibacy but couldn’t handle it by the last week.
This form of fasting strongly disciplines one’s mind and in that time I had more energy and recovered faster.
My favorite type of fasting is media fasting. No TV, Radio, Computer, Smart phone, News Paper, nothing. I do this for a set period of time.
It is difficult at first but then becomes enjoyable. The amount of free time it creates is amazing. My guitar likes it because I spend more time with it.