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Learn Before You Fast: My 3-Day Fasting Experience

I came across the idea of fasting in my research on smart health habits enough times that the benefits seemed worth any risks. Recent podcasts with guests like Tim Ferris, Dr. Peter Attia, and Dr. Dom D’Agostino all shared reasons for multi-day fasts. But would this work for a 45-year-old father of three teenagers? I decided to prepare in advance and then share the results of my 3-day fasting experience with the Personal Kaizen community.

Tuesday and Wednesday: Day 0

Sardines in olive oil - 3-day fasting experience

I looked at my work and home schedule and decided on a good week to schedule my first ever 3-day fast. My plan was to begin after dinner on a Thursday evening. To get into ketosis more quickly, I cut down on my consumption of carbohydrates (especially bread and alcoholic beverages) starting a few days before the fast. Tuesday and Wednesday I cut out my bread at breakfast and had sardines in olive oil on lettuce and spinach for lunch. Dinner both nights consisted of beef chili with some cheese on top.

On Tuesday morning my weight was 168.6 pounds, close to my average of 170 pounds. By Wednesday evening it was down to 166.8, probably simply from cutting out the carbohydrates. I checked my ketone levels both days and was reading a level of “mild-ketosis” on Wednesday evening, probably assisted by my first ever addition of MCT oil to my morning coffee (I added one tablespoon three times per day during the fast). Since I felt well-prepped to get into ketosis, I decided to begin my fast after my dinner on Wednesday – a full day early!

Thursday: Day 1

I woke early on Tuesday morning and felt fine. I dropped my daughter off early at her school and then worked from my home office. I had my normal water and coffee consumption, with extra water instead of breakfast. I added a tablespoon of MCT oil to my 9 AM coffee and visited a client job site – forcing me to walk around for the next several hours before driving home for lunch.

MCT oil - 3-day fasting experience

Wait! I don’t need to plan my schedule around meals anymore. For “lunch” I had another coffee with MCT oil and checked my ketone levels – I was in mild ketosis. My stomach was rumbling a bit at times but I wasn’t really hungry yet. I did have a bit of a headache in the afternoon.

Dinner consisted of some decaffeinated tea with another tablespoon of MCT oil. Either the several days of low-carb meals or the MCT oil (or both) seemed to be working because I was already reading moderate ketosis by dinner time.

Wait! Dinner time doesn’t matter during a fast. I’m realizing how much of my regular schedule is built around food!

For dinner, I jogged about half-a-mile for some exercise and did some push-ups and pull-ups. I also rode my exercise bike for 10 minutes at 8 PM before getting ready for an early bedtime. I still had a minor headache (not enough water!) but wasn’t really hungry despite not eating all day! My weight was down just a bit to 166.4 pounds.

Bedtime led to my first surprise. My wife reported that my breath “smelled metallic” and was not pleasant to her. After a quick internet search, it appears I was experiencing “keto-breath” due to being in a moderate state of ketosis for the first time.

Friday: Day 2

I woke up early again (5 AM) but stayed in bed thinking. My goal was to not get up too early (to conserve my energy) but I was awake anyway. Either I had become used to the metallic taste by morning or it went away overnight. Either way, I felt fine.


I still had a headache and was starting to realize it was due to dehydration. I had lots of water for breakfast and my ketone level reading was “moderate” at 7 AM. I had MCT oil in my coffee at 9 AM and in my green tea at noon. Ketone levels remained moderate and I tried to average 12 ounces of water consumption per hour.

I walked a few miles at 10 AM but was stuck in Zoom meetings from 1-4 PM. Most surprising to me was that I wasn’t really hungry despite skipping five meals in a row.

I was reading close to a “high” level of ketosis on the test strips after some water with MCT oil for dinner. The rest of my family had tacos for dinner that smelled great. I decided to work a little extra since I had all this extra time to consume that I normally spend eating.

I rode the exercise bike again and did my normal push-ups and pull-ups before bedtime to keep active. My scale had my weight at 164.6 pounds – lower than I have been in a long while.

Saturday: Day 3

I again woke up early (4:45 AM) but stayed in bed napping and watching videos on my phone until close to 7:30 AM. I am definitely in ketosis now at levels above 8.0 mmol/L. I had coffee with MCT oil for my “breakfast,” drank water, and stretched.

I had another 3-day fasting surprise: my facial skin was noticeably softer and smoother. I was also still not really hungry!

First meal in 3 days!

I visited some family and took a 1.5-mile-long walk around noontime. I was definitely feeling physically weaker and slower, but fine mentally. After returning home at about 1:15 PM I felt a little sick and had a headache. I’m not sure the cause but figured it was a lack of water so I drank a bunch.

I remained in high levels of ketosis for the rest of the day and was down to a weight of 162.8 at 6 PM. Soon after I was enjoying a nice plate of slow-cooked pulled pork with cornbread and coleslaw. My first meal in 3days! After smelling this cook all-day it was tasty!

I went to bed a little later still in a state of moderate ketosis. I believe the return of sugars and carbohydrates to my system will soon end this.

Sunday: Peaked and Heading Back to Normal

Despite my Saturday evening meal, I woke up Sunday morning at my lowest weight in years (161.2 pounds) and still measuring in a moderate state of ketosis. I had a breakfast of three fried eggs and ¼ cup of beans. I had plenty of water and some coffee. By 11 AM my ketosis reading was only mild. I’m sure that I was out of ketosis after dinner since I had lots of food at a party.

If you’re interested in seeing just how I was feeling each day, check out my digital fasting journal below!

Next week we will wrap up our discussion on fasting by sharing the lessons learned from my 3-day fasting experience. I will also provide an update on any sustained effects from the fast (health effects and weight loss) and if fasting is something I plan to do again in the future.

Please leave a comment below if this post encourages you to have a 3-day fasting experience of your own. I would encourage you to give it a try!

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