Fasting and circadian rhythms

T recently did a rather interesting post about fasting and the subsequent discussion in the comments section warrants a post of it's own on my blog because #1 it's too lengthy to explain on a comment without hogging up significant comment-space on her blog and #2 well it's an interesting topic in it's own right.

So - fasting. Either you do it or you don't. Your reasons for doing it might vary too, maybe it's something you've done all your life so you can't imagine not doing it. Maybe you're doing it to learn self control, to appreciate the things we take for granted, or dare I say, to avoid the wrath of a god. Whatever.

The point I made in T's post was that fasting probably could have a negative impact on health and well-being, looking at it from a purely biological point of view*. I make no claims on the psychological benefits (or placebo effects if you will). I'm sure people who do it year in year out feel good about it afterwards, and are filled with a sense of accomplishment and all that jazz. This post is purely about the physiological/biological impact of fasting, so if you do read this and get filled with a self-righteous urge to comment with a "don't knock it till you try it, I had an awesome time with it", please refrain. I haven't tried walking on hot live coals either, and I'm sure the folks that do it can attest to how great they feel afterwards (symbolic self-sacrificial acts of devotion et cetera) but umm yeah there are some things you don't need to try to 'knock', so to speak.

Normally, us humans tend to eat three meals a day (breakfast lunch and dinner) during the daytime hours and sleep during the night hours. During the fasting period of Ramadan both food and drink are not permitted during daylight hours, so 'fasters' eat and get more active when their bodies are 'used to' or 'preparing to' wind down for the night. This would in turn affect the circadian rhythm, leading to an increase in production of stress hormones such as cortisol and testosterone. Also well documented is the effect of fasting on the release of leptin, a hormone responsible for regulating appetite and weight (remember those genetically engineered 'fat mice' that caused a bit of a hoo-ha a while back? Those mice had mutant copies of a gene that prevented them from producing any leptin - As a result those mice were unaware of when they have sufficient amounts of fat stored so they overeat and become obese). Fasting also seems to affect the levels of melatonin, a hormone released at night to induce sleep. A brief Pubmed search also seems to indicate that fasting seems to affect sleep patterns. Delayed sleep onset and impairment of sleep structure (more importantly time spent on REM sleep was decreased) were a few of these side effects.

I'm sure that these relatively minor side effects on health are far outweighed by the positive psychological impact that 'fasters' get. As is evident by the comments on T's post, the sense of accomplishment, the "I've got the self control to actually go through with it", the "now I can truly appreciate my three meals a day and feel bad for the people who aren't as fortunate" (call me cynical, but I personally don't need to starve/mutilate/rape/murder myself to feel empathy for others subjected to the same misfortunes) and even the concept of "accumulating brownie points with god for the afterlife entry into heaven" are probably powerful enough feel-good factors to negate whatever physiological side effects fasting might have.

Personally though, thanks but no thanks.

* Of course biologically speaking, fasting can have many beneficial effects too, such as cutting down blood pressure, diabetes etc. However, that is because fasting enforces you to cut down/watch your diet, something you should be doing anyway if your BMI is higher than it should be. Bottom line - the pros of fasting will far outweigh the cons if you happen to be an orca type that snorts a dozen Krispy Kremes every hour on a normal day and then suddenly quit for the better part of the day during fasting.