thefastedcyclist.com

“Without deviation from the norm, progress is not possible.” –  Frank Zappa

I wanted to check in quick and give an update on how I am progressing.  I started my fasting experiment in early April, so it has been about 2.5 months now, and here’s where I am:

1. Work– There has been no issues with my fasting at work at all.  As I mentioned before, a 16 hour fast is perfectly suited for my job, and I have done all of the fasts that I had planned on doing without too much difficulty.

I have done some 24 hour fasts on longer days at work, and got some surprising results.  In stead of feeling tired after 24 hours of fasting, like I was expecting, I actually felt energized and great.  Normally I would have been dragging if I had been working all day and missed lunch or had an unplanned fast.

The longest fast I had was a day when I was on a 24 hour call, when I went 41 hours without eating.  I felt better during and after that call than I ever have before in the same situation.

2.  Cycling– I have been on my bike a reasonable amount in the last 2.5 months. There are 2 consistent bike rides I do: one is a longer endurance ride and the other is a difficult  interval workout.  There is a great social media/activity tracking app called Strava that I am using to track my progress on the bike. Strava uses your bike computer data, and breaks down every ride you go on and upload. It tells you time, distance, elevation gain but also breaks your ride down into segments.  It tracks your time on each segment, gives you a trophy for the fastest times on every segment, and is the perfect way to race against yourself and determine if you are getting faster or better.

My long, endurance ride I have only gone on once since I started the fasting experiment. I did that ride the fastest I have ever done it by 3 minutes, and I did it at the tail end of an 18 hour fast!

The interval workout I have done 4 times since I started fasting. I do 3 individual intervals during each “interval workout” ride.  So on those 4 interval workouts I did 12 total individual intervals.  8 of those 12 individual intervals were the fastest that I have ever ridden them.

When looking back at all the rides I have done in the last 2.5 months I have gotten 247 trophies on Strava!  Not only that, but I qualitatively feel very strong on all my rides and recover from hard efforts quicker. All-in-all the biking portion of my fasting experiment has been very successful. Fasting did not hurt my riding as I feared it could, but actually helped me to ride stronger and faster than ever before.  I will get into fat-adapted and fasting exercise in a post very soon.

3. Personal–  Since starting my fasting experiment I have lost 13 pounds!  Not only do my clothes fit better, but I have been sleeping better and feel like I have more energy during the day whether I’m fasting or not.

All things considered my fasting experiment is an astonishing success in every part of my life, and I’m excited to keep it up and see where it goes!  Thanks to everyone who has been following along, let’s see where it takes us!

There are many different forms that fasting can take. Some people fast for 24 hours two or three times a week. Some people fast for 16 hours and then eat for 8 hours a day most days. Some people even fast for three days at a time, then take a day break and do it again. There are as many different strategies as there are books on the subject (which is a lot).

The challenge that I started with was what was going to work for me. My job schedule is different every day: some days I start early, some days I start late. I often work late and almost always have to be available for add-on cases until late in the afternoon or early in the evening. Oh yeah, and some days I work for 24 hours in a row. To add a little more complexity, I do not find out what I am doing on a given day until 5 or 6 PM the night before. I have some idea how late I will be scheduled, but don’t find out the details until late the day before. This makes riding my bike very challenging during the week, and I end up trying to sneak rides in during the week when I can and riding on the weekends as much as possible.

After thinking about it for a long time, the solution to fasting I came up with is as follows: I basically have 3 kinds of days, and so I could do 3 different kinds of fasts based on what kind of day I was having.

1. Day #1 is a day when I am going to be able to go on a big ride in the morning. This is usually a weekend day. On these days it does not make sense to fast (yet that is, there will be more about fat-adapted exercise coming soon) and so I wake up and have a biggish breakfast with good amount of carbs.
2. Day #2 is when I have a big day at work, whether that’s a call or just a long day in the OR. For these days I decided I would fast for 24 hours. I know that seems like a really long time, and it is, but there are ways to make it not as bad as it sounds. I start my fast after dinner (a nice, big filling dinner) and fast until dinner the next night. I drink coffee (a moderate amount), tea, and water during my fast and chew a decent amount of gum.
3. Day #3 is most common type of day that I have. It’s a day where I am hopefully going to sneak in a ride in the afternoon, and I’m going to be working most of the day. I decided to do a 16:8 fast (16 hours of fasting and 8 hours of eating) which means eating dinner the night before, skipping breakfast, and eating lunch the next day. It is perfectly suited for my job since I cannot eat in the OR and typically if I miss breakfast the next chance I have to eat is lunch.
4. There is also a Day #4 I forgot to mention, which is where I eat like a normal person, 3 meals a day, dessert, snacks, the whole 9 yards. Because “all fast and no feast makes Jimmy a dull boy”, and also because “everything in moderation, even moderation” are words to live by.

Now I had a plan for how I was going to fast, which is the first step, but its

always easier to make a plan than it is to put it into place. And while enacting this plan I had to make sure that I was still taking excellent and safe care of patients, and make sure that my biking was not suffering.

A few months ago I heard about Intermittent Fasting (IF) from a good friend and respected colleague.  It was something that piqued my interest and also made so much sense to me that I had to investigate further.  I am very willing to try new things for health and weight loss as long as they are not detrimental to my health.   I did have some health concerns about fasting; and the first things that came to my mind were probably the first things to come to your mind as well. 1.  If I don’t eat then my metabolism will slow down and I’ll gain weight. 2.  If I don’t eat then my body will use muscle as fuel and I’ll lose muscle mass. Before I dive into those questions, let me tell you a little about me and the lens I am looking at fasting through.

First of all, I am a husband and father of 2 boys.  Secondly, I am a cardiac anesthesiologist.  That means that pretty much every day I work all day in a physiology lab using drugs to manipulate heart rates, blood pressure, respiratory rates and level of consciousness.  And on a day I am in the heart room, I use drugs to manipulate contractility (heart squeeze or function), preload (fullness of the heart), and afterload (work the heart has to pump against to eject blood).  I measure those things in real time each heart beat using some very cool technology.  Thirdly, I have fallen in love with cycling and am trying my best to become a stronger cyclist.

I decided to look closely into the above objections before I started fasting because I didn’t want to do anything to hurt myself.  The first objection that I and others have to fasting is that “if I don’t eat then my metabolism will slow down and I’ll gain weight”.  We’ve all heard this so much and for so long that we actually believe it’s true.  In reality, there’s no way that it could be true.  Even if your metabolism did slow down when you’re fasting (which there is good evidence that it doesn’t) you still have a basal metabolic rate (BMR).  Your BMR is the amount of calories your body needs every day to keep your heart beating, keep you breathing, allow your brain to work, allow cellular repairs to be made, etc.. To basically keep you alive and upright. There are many, very complex formulas to calculate what your BMR is but it’s about 2000 kcal a day for a 6’0” 200 pound man and 1500 kcal for a 5’8” 165 pound woman.  To make the math really simple, if you take in 0 calories and your body needs 2000 kcal every day to stay alive, there is no way you could gain weight.  It is impossible!

The real response your body has to fasting is to actually increase your metabolism.  This makes sense if you think about humans in terms of cavemen struggling to eat one meal a day, instead of modern people struggling to get their recommended (by many) 6 meals in a day.  If you’re a caveperson and fasting because there is no food around, and if your metabolism slowed down so much you couldn’t get out and hunt or gather, you would simply wither and die. No more humans.  No more hangry people missing their snickers bars.  Your body actually secretes epinephrine and norepinephrine (adrenalin and noradrenalin) in response to fasting which revs up your metabolism to get you out there chasing that wildebeest down for dinner.

The second objection is that “my body will use muscle as fuel and I’ll lose muscle mass if I fast”.  This was as important to me, especially as a cyclist.  In general for cyclists the rule is the lighter you are the better a rider you are.  It’s all about weight.  We talk about a power to weight ratio which is actually how engine performance is measured.  The more power you have and the less weight the better your performance and faster you will be.  But there is a tipping point where you are so light you lose muscle and your power to weight ratio actually goes down despite your weight also going down.  An example of this delicate balance is Nairo Quintana, a Columbian bike racer, winner of the Giro d’Italia, Vuelta a Espana, and twice second place finisher in the Tour de France.  These are arguably the three hardest extreme endurance events in the world.  He is 5’6” and 128 lbs. for a BMI of 20.  That is the cutoff for being underweight.  He is basically a hummingbird riding his bike up and down all those hills, and is right there on the edge of the power to weight ratio curve.  I am not Nairo and want to lose weight but not at the expense of losing muscle, so I did some research into fasting and muscle loss.  There was an article in the early 1980s called “Starvation” by Cahill.  He looked at the excretion of urea nitrogen in the urine (a product of muscle breakdown) and found that it went down during fasting.  The body is not burning muscle while fasting, it is preferentially saving it.  Jason Fung, the guru of fasting and a hero of mine, put it very well:  It would be like you chopped a bunch of firewood for the winter, and as soon as it snowed you threw your couch in the fire.  Your body does not want to burn useful protein when there is plenty of fat around to burn.

So now that my mind was at ease and my two biggest concerns weren’t concerns anymore I felt like I could start my fasting experiment.  During my experiment there were certain parameters that needed to be met.  The most important were that I had to be able to safely provide care to my patients and that my bike riding must not suffer.  The rest was up in the air, and so I began fasting.

This is my fasting journal, if you will, and how fasting has affected my life, my job, and my cycling.  I hope you will check in on me and the progress of my experiment.

Jimmy Sederberg