Mortification of the flesh is not really my thing. When my body is in discomfort or pain, it demands my whole attention - it's certainly not an aid to spiritual contemplation. So I was surprised to find how much I enjoyed a bit of fasting.
My only serious experience of fasting was one Lent, when my sister and I decided to become vegan for a while. I did a bit of research on the history of Lenten fasting, and found that originally Christian fasting was very similar to the Muslim Ramadan - they didn't eat anything during the day, but could have one meal of any kind of food in the evening. Over time, the one meal got earlier and earlier, but more types of food were restricted: no meat, eggs, dairy, alcohol or olive oil. Partly it was to do with the idea that animal products are 'carnal'; partly it was simply that they were luxuries, and often in short supply during Lent anyway.
I didn't want to do anything extreme, which could have a negative effect on my health, my ability to work, or my relationship with my family, so we just restricted the types of food but without reducing the number of meals. She became properly vegan, as she was veggie already; I also ate some fish, in line with christian fasting practice. Luckily, chocolate hadn't been discovered by Christians by the time they wrote the rules :-)
I've never been able to stick to a diet in my life, but I found that the hard-and-fast rules and the fixed length of time worked well for me - we had fun trying out peculiar recipes (chocolate cake made with vinegar, anyone?) and I lost two inches off my waist. More surprisingly, I found that it did have what you might call a 'spiritual' effect. Now, I certainly didn't starve myself - we're not talking here about some kind of religious experience involving light-headedness brought on by lack of food. But I did find that I was thinking far more about what I ate, and appreciating it more. I used to crave good food, and I was very disappointed if I couldn't have what I wanted or it wasn't as nice as I'd expected. On the vegan diet, my choice was determined not by what I wanted but by what was available. When choosing food, I found that I really did care more about following the rules than about having exactly what I wanted, and I appreciated it just as much if not more. It reminded me of something a Jewish friend of my sister's said: that it isn't the rules themselves that are important, but that following the rules makes you think about what you're doing and about God.
However, I also learned the importance of fasting with someone else. When I tried the same experiment the next year, I couldn't stick to it, because my husband wasn't fasting. I also found it hard to explain to people why I was doing it, and tended to say that it was to lose weight (which was also true). Once I started thinking of it as 'a diet' and treating it that way, it was much harder to motivate myself. Instead of having absolute, unbreakable rules, I was looking for a reward (a better figure) and that was counterbalanced by other priorities, such as keeping my husband happy with big hunks of meat and cheese! The long-term aim of losing weight always lost out.
It reminds me of something I heard on the radio which was very moving. A chaplain asked an experienced prison guard what things he thought could truly reform an offender. The prison guard replied that there were only two things: religion or the love of a good woman. It's both tragic and rather wonderful that human beings are so often unable to change themselves for their own sake, because they deserve a better life, but are so remarkably able to change for the sake of someone else. If we choose to do something for ourselves, we can always change our minds - but a promise, witnessed by others, stops us from giving up.
UPDATE: A Muslim friend has challenged me to observe part of Ramadan with him. I feel I can't really take this experiment seriously and turn down such a challenge - so watch this space...