Observations from a 4 day fast
- It’s important to eat high fat/ketogenic on the day before you fast. Doing so kickstarts the transition into ketosis which is the most important factor determining how you feel. It also seems to provide a good base for satiety during that sometimes challenging first day. Also make sure you replace vitamins and electrolytes because you’ll be depleting these over the next few days.
- Speaking of which…I cannot understand the importance of electrolyte supplementation. In a prior post we talked about the importance of maintaining salt using smart water. Now we are using LMNT, which is far superior for electrolyte support during fasting. The most important ingredient to replacing electrolytes is far and away salt. Most electrolyte waters only have a few milligrams where each packet of LMNT has 1000 mg. I am using 2 to 3 of these per day during a fast and it seems to help immensely. This was the first time I’ve ever done a multiple day fast without severe muscle cramps in my legs. In the past I have tried taking electrolyte supplement capsules and or vitamins but noticed that these would create stomach cramps and provoke hunger. Drinking my electrolytes seem to do neither.
- Sleep sucks. During the three nights of my 4 day fast I was only able to get a good night of sleep once. On the last night of the fast I slept for a whopping four hours. The crazy part is I woke up at 5 AM after not eating for approximately 80 hours and was able to do a work out and then work all day without difficulty.
- Speaking of workouts… My strength training during fasting is surprisingly good. Today after fasting for 80 hours with nothing but water and salt I was able to complete a strength session–pound for pound and rep for rep identical to what I did two weeks ago on a normal diet. Quite simply, I find that in the “short term” fasting doesn’t impact strength training.
- The importance of staying busy. This week was one of my easiest prolonged fasts (>48hrs). I think a lot of it had to do with adequate electrolyte supplementation, but much of it was certainly due to the fact that I was extremely busy at work. When you quite literally don’t have time to eat, it’s easy to work through lunch and do not think about dinner. Although I wouldn’t recommend fasting during a particularly stressful week, my opinion is it’s best to do it when you’re otherwise busy.
- About those ketones… As usual by the end of 24 hours my ketones are approximating 1.0mmol. However by the fourth day they are hovering between 2-3mmol. Ketones drop after working out and sleeping as your body uses them up.
- What about blood sugar? I always get a good laugh when I hear a non-diabetic person say “I need to eat something–my blood sugar is getting low.” How foolish. After 96 hours my blood sugar never dipped below 68 ng/mL. ironically the highest blood sugar I recorded was on the last day when I recorded 106– You read that right, after not eating for four days my blood sugar actually rose! This is because I had just finished some moderate to high intensity workout which stimulated my liver to convert whatever glycogen it was still hanging onto into glucose.
- Read the stoics. Read the Bible. Read any ancient text and you’ll find some insight regarding fasting. One of the most beautiful aspects of fasting is the mental and spiritual strength you gain during the experience. gaining power over oneself—the cravings, habits, and perceived needs—is a worthwhile goal in and of itself.
- Weight loss. Although fasting is a great tool for weight loss for those who are overweight or obese, that’s not really my goal. In fact I’m trying to hang onto muscle mass, and prolonged fasting has been shown to Cause not only fat loss but also lean muscle mass loss. By the final day I had lost only 5 pounds. When compared to prior fast where I did not supplement electrolytes as rigorously and lost closer to 10 pounds, this is a pretty striking difference. Leads me to believe that much of this weight loss is “real” and not just water weight. (note: as I publish this 1 week later my weight hasn’t rebounded significantly. fasting is good for 0.5-1 pound loss per day of the fast for me)
- What about hunger? honestly by the end of the first day hunger really doesn’t play a role. That’s not to say your stomach won’t reflexively start rumbling around noon and 5 PM each day, it’s that you just begin to ignore it and think of it like any other sensation in your body. A slight itch. A mild headache or muscle cramp. You just mentally note it, and move on. My favorite thing to do on the last day is to start planning the “breakfast“ meal… This time it was ribeye steak! Even though you might be really tempted to just binge on the last day they were two reasons not to. First, it’s very common to have significant G.I. upset once you start re-introducing food after several days. This could be abdominal cramps nausea and especially the notorious explosive diarrhea. Secondly, you’ve worked hard for four days to cleanse your body and get into deep ketosis. You might as well preserved that for another 12 to 24 hours by coming off the fast by eating high fat/ketogenic diet. (note: after downing a ribeye and even some berries and dark chocolate, my ketones were still at 1.7mmol the next day).
For more about our experience with all things fasting check out these other posts here and here!