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Friday, October 12, 2018

The 36h Fast

36 hours has been my longest fast to date.

I'm not sure I will push it further - I might.  It went fantastically well.

I Gots Energy!

I feel fantastic.  I have energy, I'm not tired.  I'm not hungry. My mood is great.

Sure there were a few dips during the 36h, and the odd hunger pang - but I have dips every day, and odd hunger pangs. 

In fact I would say my hunger was less than between meals on a regular eating day!  And way less than when I try to reduce calories. I think that's what makes fasting so appealing (and, frankly, bizarre).

I did something to make it a bit crazier - I ran 15km at the 22h mark of the fast, on just water.  Well, technically, lemon juice and water with a bit of salt... to each one's own!  No calories, though, which is the main point.

I was slower than I'd have been fully carb'd up carrying a bottle of Gatorade - no question. But I did it, and didn't feel bad.  I've done a few fasted runs leading up to this, so I figure it's my body adapting.  In studies fat-adapted athletes were able to metabolize 2.5 times as much fat as high carb athletes.

Fat For Fuel

Fat is not as efficient of a fuel - true. 

Fat is not already in your muscle like muscle glycogen is - true.

But there's a whoooolllle lot of it.  If one turns to ultra-endurance then fat is going to be a big part of how you get to the end.  Better learn to burn it for fuel!


I'm down about 8 pounds since September (some I'm sure is water/etc!) as of this morning, 36h fasted.  Even unfasted I'm down ~4 pounds, so some of it is definitely real weight loss.

Going to keep on it!  Feels like I finally hit on something that works.

Tuesday, October 9, 2018

Fasting Update - 6 Weeks In - Low Carb High Fat Experiment

Time flies when you're not... eating.

I wasn't seeing weight loss results, so I've changed a few things.

  • Longer fasting periods
  • Low carb / high fat meals to break the fast (or just before it)
Low Carb / High Fat (LCHF)

Edit: Just after I posted this - I listened to this VeloNews FastTalk Podcast.  If you have an hour, it's way better than reading "books" and "articles" or this "blog post"... I highly recommend it... he actually backs up almost everything I said below - for the recreational athlete, there's really no reason not to try a ketogenic diet... 

I'm guessing this is the most contentious.  I've also had the hardest time finding any information on athletic performance in the absence of carbs.

Finally I found two resources: this book was the first one, "The Art and Science of Low Carbohydrate Performance".

It wasn't about fasting (at all) but it did focus on using fat over carbs as fuel for endurance performance.  There are several studies and anecdotal evidence from Ultramarathon runners and such that suggest you can train your body to burn fat efficiently enough to get decent performance.

This was an exciting notion.  Best of all, I wasn't alone - there were others trying to train on empty, and even (gasp!) studies!  And folks who found real success with it.

I was chuffed.

But... I since found a study that throws some water on this notion.

The good:
...the fat-adapted athletes were able to sustain a fat-burning rate of 1.57 grams of fat per minute, which is 2.5 times greater than their “normal” values.

2.5 TIMES the fat metabolism during exercise compared to before they were "fat-adapted".  That's extremely relevant statistically, remarkable!  Considering just how much fat the average person has (enough to run/bike for weeks!) it's awesome that it's able to be tapped into to a greater degree!


...both high-carb groups improved, by an average of 190 and 124 seconds, respectively.
In the LCHF group, on the other hand, the gains in VO2max were countered by the decrease in efficiency. The result was no change in race time (they were 23 seconds slower, on average, a difference that wasn’t statistically significant)

So you start to burn more fat - which is great - but it makes you less efficient.  Ultimately, this means your top-end pace is lower, so your performance... droops.

Womp womp.


This made me think about what my goals really are.

Are they athletic performance?  Going long even if it's slow/slower?

Or just losing weight and being as healthy as I can be?

For me it's a no-brainer - I want to lose weight and be healthy.  If I can do that with a LCHF diet, I'll take being less efficient.

Also it's worth noting - VO2max comes into play when you're close to balls-out, not when you're doing an ultramarathon or a really long adventure race.  I'm doing a 24h bike race and a canoe race that'll take close to that - so being able to tap into fat for energy probably helps me a lot more than being super efficient at VO2max.

Or, per the Runners World article:
there may be a difference between Olympic-bound athletes like the ones studied here and recreational ultra-endurance athletes whose goals focus more on completing the distance than sustaining near-threshold intensities or being ready to respond to high-intensity surges from competitors. At lower intensities, the negative effects on efficiency may become irrelevant.
So I'm pretty happy continuing to keep trying to meet my endurance goals with a LCHF diet, as well as with fasting.  Everything I've tried so far has gone reasonably well - at slower paces.

Longer Fast Periods

Instead of 16:8 (16h fast, 8h feast), I've been pushing the 16 longer.  Last week my fast lengths were: 22h, 9h, 17h, 14h, 22.5h, 19.5h, 15h.  A few cheat days in there - whoops.

The biggest challenge has been pushing through lunch on work days.  If I'm at home and keep myself busy I'm fine, but at work my brain power seems to lag.

I would like to get into the 24-36h range but it's been a challenge.  Mostly it's hard to miss the family meal at the end of the day.

Weight Loss

I'm down about 3-5lbs so far.  It's hard to tell for sure, as when I'm glycogen depleted and LCHF the scale says nicer things than after I binge on carbs for an evening... but minimum 3lbs.

So I feel there's some progress, and if I stick to it............ more progress!

Sunday, September 16, 2018

Fasting Update

Image result for dinner plate
Dinner Time!

I've been fasting for 2 weeks now.
My longest was 26 hours, but I also did 24, 20, 19, 18, 17, 16... I've been trying to just fit it in with my life, which isn't always that easy!

Brain Fog

I'm having some difficulty with fasts that go through the work day.  If I break the fast at lunch I'm good, but the afternoon gets my brain going a little squirrely.  I don't know how to describe it exactly - I'm not exhausted, just feel "off" in the head.

Feels like my best bet is actually 24h fasts that go lunch to lunch. But then I miss the family dinner "ceremony" so I'm still figuring this out.


I've been trying to keep on the exercise, and mostly that's been great!  I've been doing my running/biking at a moderate pace if it's later into a fast, but if it's near the start I use it as a way to deplete glycogen sooner. 

It's a complete mindset shift - when you're a runner/cyclist, you're always told to eat to train, then get home and eat to recover.

I've been most surprised by the cycling.  It's crazy to me that I can go for 2, 2.5h on the bike without bonking.  Just have to watch the intensity - when I'm actually training for something, I will have to figure that part out.  Presumably I'll do my cycling during the non-fasted state and consume stuff on the bike.

Weight Loss

So far... nothing.
Image result for friar tuck eating
Me Enjoying my Feasting Period
Now I have to assume that the "Insulin Resistance" problem takes more than a couple weeks to resolve. But I need to eat better - in the eating windows I've been feasting like Friar Tuck.

I also haven't been very good at reducing refined carbs, one of Dr. Jason Fung's pillars of health and lowering insulin levels.

"Reduce intake of refined grains and sugars, moderate protein consumption, and increase natural fats"

... sounds good, but I whip up some guacamole (natural fats!) and then eat it with... chips (refined grain).  Because it's delicious that way.  Dr Fung suggests condiments mostly (olive oil, butter, etc) - but they have to go on something.   Dairy fat is the one that's easy (mmm cheese!), I guess I can feast on nuts and avocados a bit... I should really google some high fat recipes.

Friday, September 7, 2018

Fasting and Endurance Sports - Part 2

Velonews Fast Talk episode 23


They talk about "periodization" of nutrition, and a lot about "low carb" states!

The long and short of it - in non-competition phases when your intensity isn't as high, there are times you'd want to train in a low/no-carb state.

"Not throwing carbohydrates in massive quantities at every training session" ... which he says is the "old advice".  I think it's also the advice every manufacturer of sports drinks and gels wants you to take!

In the "Build" phase - his suggestion is to have a high intensity session in the evening, recover with high fat / low carb, sleep, then wake up the next morning and do a lower intensity session in a low-carb state.

He also stresses the need for carbs for intensity - this stands to reason.

"How often should you be training with low carbohydrates?"

No more than 2 times a week, in the "Build" phase.

Etc!  It's a great listen.


He doesn't address fasting specifically, and his focus is on getting the best cycling results, not losing weight.

I haven't been "racing" and I'm certainly not an "elite athlete" so my focus right now is on weight loss, not on training adaptations.

Glad to hear though that while I'm meeting my weight loss goals, I'm not totally out to lunch on the endurance training side.  Low/no carb states aren't incompatible with training.  It will just be a question of finding the right balance.

Monday, September 3, 2018

Fasting and Endurance Sports

I've dabbled with fasting in the past - but I'm getting into it more seriously now.

I recently read The Obesity Code by Dr. Jason Fung.  He makes a compelling case that the old advice "Eat less, Exercise more" is ineffective.  And this is backed up by studies showing almost nobody keeps off weight with that approach.

If you don't feel like reading an entire book (although it's great!), then check out this video... hits the key points.

The book is mostly not about fasting - he actually doesn't bring it up until the very end.  Instead it explores the advice we've generally been given, and the science of why we are fat.

His claim is that the root of the problem is hormonal, and primarily insulin.

Boiling it down: we are fat because of what we eat and when.

The What:  Sugar and refined carbs.  These create elevated insulin responses that ultimately lead to reduced insulin sensitivity, which result in more insulin, which makes us fat.  He also takes aim at artificial sweeteners, which provoke an insulin response despite having no sugar in them (!). 

The When:  Snacking, snacking, snacking.  We eat too much, and the advice to "graze" makes it even worse.  Our bodies are flush with insulin, always, which just makes the body numb to it... which again leads to even more insulin, which makes us fat.

This is where fasting comes in.  There are various approaches, but in all cases the idea is to reduce insulin for long periods of time by not introducing new glucose into the bloodstream, thus no insulin response.  This in turn has been shown in studies to increase insulin sensitivity, which he argues is the cure for obesity. 

My Weight, and How I Will Apply It

I was an outlier in 2014... and had a bit of swagger about it.  I had lost weight and held it off for 10+ years.  I did it through calorie reduction and exercise. And it was bloody hard.

I'm not anymore.  I weigh 212lbs, vs the 235lbs I weighed at my peak - but I'm almost 30lbs above the 185lbs that I need to be "Normal" rather than "Overweight", and a good 40lbs above where I'd like to be.

Fasting - in the past I had done 16:8 - basically not eat except between noon and 8pm.

But I think the 24h/36h fasts he suggests sound like they may be more effective.  Fast for 24h 2-3 times a week, rinse, repeat.

Wither Endurance?

Dr. Fung is very clear that exercise is good for you - it has a lot of hormonal effects, including increased insulin sensitivity and reduced Cortisol (stress hormone).

However he is very down on the role it plays in weight loss.  Burning calories via exercise is not the way you will lose weight.

He mentions exercising while fasted is a "good time" - but it sounds like he's mostly talking about gym rats (and he even references the Lean Gains guy).

... so where does endurance exercise fit in?

I found this very excellent chart.


At low intensity, the body burns mostly fat (which I have a lot of!), so it's possible to go for a long time without using up the body's glycogen or consuming additional sugar.

At high intensity, the body burns mostly carbs, so it either needs to be short or you can't be fasted.

I've done runs as long as 16km while fasted for 16h before - they were slow and pretty horrible.  I don't know if they get better, I think it's just something I'll have to experiment with.

One more beautiful chart, from the same source...

... so as you can see, the probability of hitting "the wall" (running out of carbs) is nearly zero when the "running intensity" is under 40% of VO2 max...

This is probably down to one's personal fitness/genetics/weight/etc - but I this all points at it being possible to run long slow runs, fasted, with nothing but water and electrolytes.

My goal right now is to lose weight, not to run a marathon - so I'm not so worried about this.  If I can run long I'll run long.  If I can't I'll put that on the back-burner until I can.

It will be an interesting journey, if nothing else!

Monday, July 23, 2018

Sinusitis, Rockstar, Running Whilst Sick

I've had a horrible case of sinusitis.  It has taken me down for the last 2+ weeks... felt like a cold at first, thought it'd pass in a day or two, or three... but now on day 17.  Halfway through a bout of antibiotics and feeling a bit better, but still not 100%.

I missed Rockstar.  It's one of my favourite races.  Sadness.

Running Whilst Sick

I tried a run early in the illness - that was a bad idea.  It went horribly, and probably made it worse. 

This weekend (day 14/15), despite still being fatigued and my throat being sore and phlegm still flowing...

... I said "screw it" and ran again.  Short runs, slow, they were tough, but I didn't feel bad after.  I think it makes a big difference whether you're on the start or end of the illness.  I'm getting better, slowly, but this has really sucked.  Especially in summer.


Monday, July 2, 2018

Humidex, Wind Chill, and Other Fake Weather Things

Ahhh, summer, the time of year when we like to exaggerate how hot it is.

The CBC had a great article some years ago about just how and why the Humidex, a Canadian invention, is flawed.

It's especially important for us runners and cyclists, as we may miss other factors that are equally important!

In no particular order:

  • Humidity - when it's very humid, sweat doesn't evaporate well to cool you down
  • Sun - this is massive - I especially notice it in winter.  A sunny day at 0C feels a lot warmer than a cloudy day at 0C!  Running at noon vs early a.m./p.m., even at the same temperature, is much more difficult.  The direct rays add heat to your body that you need to then expel. 
  • Wind - the one thing that makes cycling more tolerable than running in hot weather is the speed of travel generates more wind!  Ahhhhh. 
    It's remarkable, I biked yesterday for almost 4 hours in +32C (+36C with the fake Humidex, and in the sun!) but it felt... ok. 
    Today I ran in cooler temperatures and died by the end.  I'm still sweating and that run ended half an hour ago.
  • Clothing choice - black in the sun?  Long sleeves?  Etc!  So many ways to either help or stop your body from cooling itself down.  I used a singlet today - it really helps with the air flow.
... etc.  

Feels Like? 

And, as the CBC climatologist notes, "no two people react the same way to weather. Age and health, including respiratory issues and fitness levels, affect how hot it feels".

So when they say it Feels Like 36C  - first of all, what day's +36C are they comparing to?  A sunny dry day with no wind?  Cloudy?  Windy?  Who knows!

And each person is different, so what might feel like +36C to one person might feel like, I dunno, +42C to another.

Who Cares?

Yeah maybe.  But I think it's worth paying attention to the other factors and knowing how one's own body reacts to them, rather than just blindly taking a number that "Big Weather" throws out there.