I've been practicing intermittent fasting for over 3 months now. It's time to share that experience and decide what to do next.


What is Intermittent Fasting?

Simply put, intermittent fasting (IF) is when one alternates periods of eating and periods of not eating (fasting). The fasting periods can be long or short and their intervals as little as once a month or as many as several times a week. 

The method I picked to start with is the 24-hour fast once a week. Why? It seemed the easiest to start with. The only other regimen that uses less than 24 hours fasting is the daily 16-hour fast, which seemed like too much commitment for someone with no experience in fasting.

I will describe the once-a-week protocol in just a moment. But before, let's review why I chose to fast.


Why fast?

For years, there has been scientific evidence of the benefits of caloric restriction (CR): it extends life and reduces incidence of age-related diseases like cancer. That's been extensively shown. But that's living with about 70% of our daily calorie needs. And that's very hard to do -- one is always hungry, who wants to live like that?

Researchers recently turned their attention to a more realistic approach and one that mimics what our predecessors have done for centuries, not because they liked it, but because food was scarce and unpredictable. They looked at intermittent fasting. 

Intermittent fasting has been shown to provide similar benefits as caloric restriction, namely disease prevention, insulin sensitivity reduction, various blood-lipid improvements, etc. Here's what one lead researcher had to say about IF and CR:

"[IF and CR] enhance cardiovascular and brain functions and improve several risk factors for coronary artery disease and stroke including a reduction in blood pressure and increased insulin sensitivity." [source]

So, it's possible to obtain the benefits of CR without all the continuous pain of starving oneself? Sign me up.

My motivation, however, was partly to try a new challenge and partly wishful thinking that by doing so, I'd kill off possible senescent, pre-cancerous cells. It's been shown that by starving the cells from nutrition, the first cells to die are those that are already unwanted anyway, the ones that have been dividing erratically and would have been purged by our immune system when it's working at its best. Or so the theory goes. And early research seems to support this theory and has shown in rodents as well as in humans that fasting aids in cancer treatment if done in combination with chemotherapy.

Also, the theory goes that fasting is a mild form of stress -- a good kind of stress. "The hypothesis that during the fasting period, cells are under a mild stress, and they respond to the stress adaptively by enhancing their ability to cope with stress and, maybe, to resist disease.” says one researcher.


The regimen

Armed with that knowledge, I decided to try a 24-hour fasting period every week. While most articles say that 10-16 hours are enough to start capturing the benefits of IF, others point to longer periods like 3 or 4 days. Since 10 hours of fasting is almost a no-brainer (sleep plus a delayed breakfast) I felt I needed to push it a little more. Twenty four hours seemed like a good period to start with.

I picked a Tuesday to start my fast. My first attempt was to eat dinner on Tuesday and then eat nothing but drink water and green tea until dinner on Wednesday, as measured by the time I finished dinner on Tuesday. The first day proved surprisingly easy for the most part. Somehow, I was busy enough that skipping breakfast and lunch were not a problem. But the mid-afternoon was a little harder. The last 4 hours were not painful per se, but all I could think of was what time I could eat again. Because I had eaten a late dinner on Tuesday night and had finished around 8:30pm, I had to wait until then on Wednesday to start my next meal. And by 4pm I was already getting a little cranky.

The next two weeks went the same way. My hunger did not bother me until around mid-afternoon, when I typically have a snack, usually nuts. I had been drinking tea (actually, yerba mate, which I love) the whole morning, but drinking a caffeinated beverage so close to bed time was unwise, so when mid-afternoon came around I resorted to using herbal teas in the last hours of my fast. Having something warm in the belly helps a bit, but it doesn't do much to the anxiety of getting close to being allowed to eat again.

Then, after two weeks, I switched my strategy. I decided to do my 24-hour fast from lunch to lunch. That would mean that sleep is in the middle of the fast as opposed to being in the very beginning. I figured that would help get my mind off food towards the end of the fast. And it did, it worked. Having lunch at around noon on Tuesday and then eating again at lunch time on Wednesday proved to help a lot. Because waking up is a slow process for my stomach in general, I did not notice the hunger until mid-morning, but by then I'd be just a few hours away from eating again and I could drink as much green tea and yerba mate I wanted to curb that remaining hunger.

Over the next several weeks I repeated this protocol and it has gotten easier. So much so that I'm now tempted to try longer periods of fasting.


Noticeable Effects

Sadly, I have not noticed much of an effect from months of practicing this weekly fast. I do feel leaner when I'm fasting, but I haven't noticed any significant weight loss. But I also wasn't looking for one. As I said, my goal is to "purge" the body from possible pre-cancerous cells and live healthy. Weight loss, if any, is icing on the cake -- the cake I don't eat when I'm fasting or ever, as I'm not prone to eating much of these toxic substances

I haven't measured anything in the blood either or taken MRIs to find decreases in possible pre-cancer cells, so I don't know what effect it is having (I wish I had measured and if you know of any cost-effective way of doing all necessary tests to measure this, please let me know in the comments below).

However, I haven't noticed any problems either. I'm not sluggish or cold or tired or anything. The only downside is a little crankiness in the last two or three hours of my fast. I still think about food then unless I get busy with something else and have some hot yerba mate in my stomach.

Overall, I can't say. But I like the challenge and the research so far, so I will keep doing it for now.


Going long

It's not clear to me yet whether the benefit of doing longer fasts is worth the effort. However, several health-enthusiast bloggers and researchers seem to agree that fasting is only a pain in the first 2 or 3 days and that a very long fast of 7 to 10 days or longer is not only safe, but painless after the first few days. It is said that after hunger subsides in the second or third day, it's gone for a long time and re-appears after a while - for some, ten days for others, 28 days -- which is when you know you should break the fast.

I haven't found much evidence that this mode of living will do me any good, but I want to try it for the challenge and to see if there are other obvious effects, perhaps weight loss or muscle mass growth (yes, that is one of the alleged effects of prolonged fasting, the metabolism goes up, not down as with caloric restriction).

Here are some resources I found useful. The first video is a good summary in twelve minutes and talks about the benefits of longer fasts.

What I've Learned - Fasting vs. Eating Less: What's the Difference? (Science of Fasting)

Dr. Rhonda Patrick - Science of Fasting

Tim Ferris Blog - Dom D’Agostino on Fasting, Ketosis, and the End of Cancer

Fasting-like diet reduces multiple sclerosis symptoms


 I hope you enjoyed reading. Let me know if you are on any kind of intermittent fasting regimen and whether you've taken the plunge into longer fasts. I'll report my findings here when and if I attempt it.