What I Learned From Not Eating For 5 Days

Recently I listened to a fascinating podcast during which Tim Ferriss interviewed Dom D’Agostino on fasting, ketosis and the end of cancer. (You should definitely give it a listen). The podcast piqued my interest in these topics, and I decided to do a little digging. It turns out that fasting isn’t just some new fad diet. People have been fasting (or starving, or cleansing, depending on how you want to look at it) since the beginning of people. Some fast for religious reasons, some for weight loss, and others for general health and well-being. There are tons of different types of fasts, too, ranging from intermittent fasting to juice detoxes, dry fasts, partial fasts, the Master Cleanse, and more. But the general idea is the same for all of them: diet restriction.


Really? This is your diet..?

Having just returned from a trip to Asia, I was experiencing a myriad of health concerns, some of which I thought could potentially be fixed by fasting. I’m generally opposed to fad cleanses or diets which may or may not work based on very little research. So if I was going to do one at all, it was going to be the hardcore one – water fasting with zero calorie consumption (did I mention that the first race I ever registered for was the Death Race? I don’t half-ass things). As I mentioned, everybody fasts for different reasons and to accomplish different results. These are the main things I personally set out to achieve:

Previously I had tried intermittent fasting and 24-hour fasts, so this time I decided to reach further out and try for 5 days, leaving the option open to break the fast at any point if I ended up feeling really, really terrible. I settled on 5 days because some literature I read suggested you really only start to reap the benefits after day 3, but I didn’t want to commit to a full 7 since I wasn’t planning on doing the fast under medical supervision, (see my disclaimer at the bottom), and this was going to be my first ‘real’ fasting experience.

Timing-wise, I picked a week to fast during which I didn’t have any social plans, or commitments to physical activities. I knew that I could expect to feel low energy, so I didn’t want to set myself up for failure or flakiness.

One additional thing I decided to do was assist my hydration with saltsticks supplements, taking two per day. This was simply to aid in water absorption. Aside from these, the only thing I consumed for the whole 5 days was plain, simple water. I tried to drink only filtered or distilled water, rather than water straight from the tap.


So here’s how it all went down:

3 Days Before Fasting

  • For three days I tried to eat a ketogenic diet. I won’t go into the details about what that looked like, here, because that’s a whole other topic. But the purpose of eating this way was to get my body into a state of ketosis, where it was already used to burning fat for energy, rather than glucose.

Ketogenic Diet

Day 1

  • Everything felt peachy for most of the day until later in the evening when I felt a bit low energy, remedied by simply going to bed at a reasonable hour.

Day 2

  • I reluctantly woke up and sluggishly went to work. I felt extremely lethargic and “empty” all day. My mind felt cloudy and I couldn’t concentrate on anything. I sat at my computer accomplishing very little and simply wanting to go to bed.
  • I craved food like mad, almost all day. I day dreamed about burgers and hot wings, pizza and candy. I felt quite a bit of stomach discomfort as my belly gurgled and grumbled and felt like it was digesting itself.
  • Slight muscle and back pain.
  • Had to check my head space and not act like a monster toward co-workers and friends. Felt difficult to hold a conversation, and like I gave rather curt responses to people.
  • Felt very cold and had to wear lots of layers.
  • Seriously considered ending the fast, but convinced myself this was mostly an emotional response, as I was clearly not dying. Even though human instinct was kicking in telling me “you need food, or else you’re going to die”.
  • I went to bed at about 8:30pm, completely sapped of all energy.


Day 3

  • After sleeping for nearly 11 hours, I woke up feeling surprisingly good and well rested.
  • In the morning I still felt a little foggy, but by the afternoon this cleared up and I started to have more mental clarity.
  • My energy levels seemed to improve overall, and I craved food a lot less. Unless I smelled someone else’s food, and then the food cravings re-surfaced and I nearly caved in to food a few times.
  • By the end of the day the feelings of “emptiness” were completely gone. My belly didn’t grumble anymore.
  • Still felt cold.

Day 4

  • Great, long sleep.
  • Excellent mental clarity.
  • No hunger pangs.
  • Very good level of energy. I don’t think I would have been capable of going for a run, lifting weights, or any activity that required a high energy output, but for regular daily movements I felt fine.
  • Started menstruation earlier in my cycle than usual. I’d read online that this has happened to many other women 3-4 days into their fasts. I’ve yet to figure out why, exactly, but in the end it’s just another way the body ‘cleanses’ itself, I guess.
  • Still felt cold.

Day 5

  • Another great sleep.
  • Much like day 4 I continued to feel “fine”. Certainly not “jump up and dance” energetic, but I definitely didn’t feel like I was suffering.
  • Seriously considered extending the fast to 7 days, just to see if it was possible, but decided to stick with my original plan for 5 days.
  • Still felt cold.

Breaking the Fast

  • At the end of day 5 I was allowed to eat again! I started consuming nourishment at a slow pace, just sipping on small quantities, and relying on liquids to ease my digestive system back into operation after getting quite the rest.
  • The first thing I drank was Well Juicery’s “Be Well” juice (beet/carrot/apple/lemon/ginger), which tasted like actual heaven.
  • The second thing I ate was a delicious homemade tomato basil soup, which literally tasted like the best thing I’ve ever eaten.

How funny is this stock image?

So what are some takeaways or tips I’ve learned?

  • I learned some valuable lessons about my own emotional attachment to food. I mean obviously it’s a physical necessity, but I put some time into reflecting on why I eat and when and how much. Fasting shone lights on my eating habits, such as when I eat out of boredom or because of a schedule, rather than because of actual hunger. In relation to this, I also reflected on the types of food choices I make, depending on my mood. I also considered food nutritional quality and portion sizes. Finally, I thought quite a bit about how we as a population often over-eat and then feel like we have to balance it out with exercise, when really exercise should not be punishment or atonement, but simply an enjoyable activity. (I thought about food a lot, obviously).
  • It wasn’t an intended purpose, but I did end up reflecting quite a bit on real, true hunger throughout the world and how terrifying that must be for so many families. At any time I could have easily broken my fast. I had willingly chosen not to eat, while so many people out there starve to death every day, and certainly not by choice. At no point did I experience stress related to whether or not I’d be able to eat. This thought made me feel guilty for stretching my luxury into a realm I can’t actually begin to understand.
  • On a lighter note, I’d recommend going into a fast with a list of things to do instead of eating. Cleaning, art projects, books, movies, errands, walks, travel research, light yoga…anything to keep you busy, especially at usual meal times when you’d otherwise be eating.
  • Expect to sleep long hours, and feel cold the entire time.
  • Don’t expect to get a lot of exercise, but definitely try to keep some level of activity such as light stretching and walking.
  • You will never appreciate food more than directly after a fast. Everything tasted better, flavours were more pronounced, and food felt that much more satisfying than any other food I’ve ever eaten.
  • The day after I finished my fast (Day 6) my energy came back with a vengeance and I was in an extremely good mood all day, almost like nourishment was a drug.
  • Since finishing the fast, my sugar cravings were initially gone, but have slowly creeped back. Though I do seem to find them easier to control.
  • I estimate that I lost about 5 pounds in 5 days. This seems to be the standard when fasting: 1 pound per day.
  • I drank approximately 3L of water every day, which felt about right for me.


In sum, would I do it again? And if so, what would I do differently?

  • Yes, I would do it again! I’m even thinking of making it a quarterly occurrence (see the “cancer as a metabolic disease” research and why this is actually recommended) and extending the duration to 7 days. It was a really positive experience (other than Day 2…)
  • I’d possibly experiment with drinking more water to see if it improves my energy level at all.
  • I’d definitely eat a ketogenic diet properly and for more days before going in to the fast. I’m not totally sure whether or not I was actually in ketosis before the fast began, which may have contributed to my monstrous mood on Day 2.
  • I’d take more biometric measurements before, during and after to plot some interesting data. In particular I’d like to measure body weight, blood pressure, glucose levels and ketones.
  • I would like to experiment with meditation during the fasting.

Disclaimer: I don’t want to suggest that you try fasting, unless you feel that it’s right for yourself. And if you do decide to fast, take note that typically fasting is not recommended without medical supervision. Our bodies are all different. Talk to your doctor before you try it.


  1. Justin March 18, 2016
    • Michelle March 18, 2016
  2. Don May 16, 2016
  3. Curtis September 23, 2016

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