The Psychological Effects of Intermittent Fasting

Hunger doesn't have to be a negative experience. (Photo by SuperFantastic)

I've noticed recently that whenever I tell people I'm doing intermittent fasting, at first they're usually very interested in why and how I do it. After explaining the details, however, they suddenly get very defensive and start coming up with reasons for not fasting themselves - even though I'm in no way trying to promote fasting. I'm simply stating my personal reasons for doing it, and though I believe the health benefits are universal, I'm not suggesting others should do it.

This psychological phenomena is interesting, and I feel it's not only applicable to intermittent fasting but to other things related to health and lifestyle as well. When you tell people that you've done changes that can be perceived as radical (even though they might not be so radical) and that require some effort, people often start rationalizing why they couldn't implement the same changes in their own life even if they wanted to. Thus, the reasons are more on the lines of "I can not do x because of y" than "I don't want to do x because I enjoy y more".

To me, this has always seemed like a strange approach. Why do so many people feel the need to have any other reason for doing or not doing things than personal enjoyment? It is a perfectly valid reason, after all. For example, I'm aware that caloric restriction is most likely superior to intermittent fasting in terms of longevity, but still choose not to do it because, well, it really is a hassle (read about my week-long experiment with CR here).

The most common objection to intermittent fasting I hear is that "my body simply couldn't cope with it", as if it were something only a small fraction of people could reasonably do. People say they need to eat regularly or else they will feel "tired" and "irritated", which apparently is a result of low blood sugar. Certainly blood sugar can have that kind of an effect, but who says it's a permanent one? The body is quite good at adapting to different kinds of environment, and as far as I know, there is no genetic reason why anyone in normal health could not go without food for at least 24 hours.

If you're used to eating three square meals a day, a good tip is to get into intermittent fasting slowly by shortening the eating window from one end little by little. For example, if you normally eat from 8 AM to 11 PM, try eating from 9 AM to 11 PM (or 8 AM to 10 PM), then 10 AM 11 9 PM (or 8 AM to 9 PM), and so on. This way your body will get used to being without food for longer periods of time. When you feel comfortable with it, you can switch to using cut-off points (i.e. eating from 6 PM one day to 6 PM the next day, or whatever you think is the best time of day to either start or stop eating).

Another tip is to mentally associate the feeling of hunger with good things instead of bad things. When you feel like eating, don't think of it as some kind of a emergency signal that must be obeyed blindly but as a sign that something good is happening inside your body - that you are in fact experiencing the health benefits of intermittent fasting. We're not talking about starving here. Hunger will not kill you.

There's some controversy over whether caloric restriction affects mood negative or positively, and while intermittent fasting is not exactly the same thing, they do share many of the same benefits. This study reports that when your body notices it needs more calories, levels of a hormone called ghrelin increase. Ghrelin is known to trigger hunger, but the researchers discovered that its main function is to reduce stress. Mice with low ghrelin levels seemed depressed, while mice with high ghrelin levels were more social and energetic.

It's difficult to say how significantly intermittent fasting by itself has affected my mood, but I definitely haven't experienced anything negative so far. Granted, sometimes when I get really hungry during a fast, I feel fatiqued, but it is more a physical effect than a psychological one - the fatique is not accompanied by depression. And quite often fasting seems to give me a very energetic and happy mood, which has been one of the best parts of this experiment.

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