Intermittent Fasting and Endurance

A light bike doesn't replace good fitness.

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kevinkalis
Posts: 597
Joined: Tue Aug 03, 2010 6:29 pm

by kevinkalis

Found this article recently:

http://www.leangains.com/2010/05/fasted ... e-and.html

I'm a big fan of Intermittent Fasting, having sampled it mainly during my off weeks. It's fantastic for weight loss but I'm looking at continuing it into my training to continue the results.

I'd like to get a few opinions on this. I don't mind if the gains don't match up to the findings quoted by that article, I just don't want it to be detrimental to my training.

Any questions about the intermittent fasting protocol you can direct at me and I'll answer them as best I can based on my knowledge from the website. Or you can read the various articles on the website, I highly recommend it.
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dustbin
Posts: 357
Joined: Sat Oct 24, 2009 7:43 pm

by dustbin

I personally believe that fasting should never be done for the purpose of weight loss, but I agree with what the article is saying. I do the majority of my training rides very early in the morning (8am or earlier)... not because of time constraints, I just like to. If the ride is less than 2 hours long, typically I do it without eating any breakfast or eating during the ride. I usually carry some food to eat when I am doing my cool down. I also have a snack when I get home before stretching/shower. Then I eat my meal (which is still usually within 30-40min of getting home). I usually don't eat any breakfast before longer rides, but I do eat during the ride.

I have never felt like it has made my performance suffer (power meter supports this)... and I feel better when training on an empty stomach. I can't prove that it's helped my training or physiological adaptations... but it seems to be working for me! I've hit no plateaus and see steady improvements in fitness.

by Weenie


kevinkalis
Posts: 597
Joined: Tue Aug 03, 2010 6:29 pm

by kevinkalis

dustbin wrote:I personally believe that fasting should never be done for the purpose of weight loss, but I agree with what the article is saying. I do the majority of my training rides very early in the morning (8am or earlier)... not because of time constraints, I just like to. If the ride is less than 2 hours long, typically I do it without eating any breakfast or eating during the ride. I usually carry some food to eat when I am doing my cool down. I also have a snack when I get home before stretching/shower. Then I eat my meal (which is still usually within 30-40min of getting home). I usually don't eat any breakfast before longer rides, but I do eat during the ride.

I have never felt like it has made my performance suffer (power meter supports this)... and I feel better when training on an empty stomach. I can't prove that it's helped my training or physiological adaptations... but it seems to be working for me! I've hit no plateaus and see steady improvements in fitness.


Well, that's certainly encouraging. I wouldn't do anything in excess of 2 hours training on an empty stomach without taking some energy gels etc. That'd just be asking for trouble. My main concern is just that I don't want to hinder my training.

As a whole, I like the idea of intermittent fasting. Basically, you're still eating the same calories as you would normally, depending on your goals but, it's just sandwiching all your meals into an 8 hour period. I highly recommend reading some of the other articles on the site.
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coachrobppc
Posts: 5
Joined: Wed Dec 29, 2010 9:41 pm

by coachrobppc

I have also done this a couple of times a week during both the off season and the race season with little or no noticeable loss in power. In the off season I will ride right after waking for 30-45 minutes prior to eating anything. I will take coffee with me but that's it. I will also do this durring the race season but only on rest weeks.

In the off season I have seen the biggest losses doing this. During the race season I only do this to manage weight.

dustbin
Posts: 357
Joined: Sat Oct 24, 2009 7:43 pm

by dustbin

After reading through the rest of the blog (at least a lot of it) and familiarizing myself with his philosophy... I'd say it's nothing TOO special, but it is against modern/conventional wisdom (in terms of meal frequency and metabolism). I follow a lot of the principles of natural hygiene, and they advocate something pretty similar to intermittent fasting. Stuff like don't eat if you're not hungry, eat meals but not snacks, etc. However they seem to favor eating earlier in the day and beginning your fasting more like 4-6pm (which I would think is better if you're not waiting until the evening to exercise and/or you are doing endurance sports).

I myself usually don't start eating until about 8am (unless I'm doing a >2 hr. ride) and I typically don't eat after about 5pm. I didn't do this because of any particular dietary philosophy, this just seemed to make me feel the best through trial and error. So I am pretty close to the 18/6 protocol he is doing. I think there are great advantages in digestive efficiency as well by doing something similar to IF (and not also not snacking). 18/6 is a very realistic protocol as opposed to 20/4 or more extreme.

I asked a couple of friends of mine who are fasting supervisors about their opinions and basically said that you will get better at what you train (duh!). If you train with lower glycogen stores you will become more adapted to performing under these conditions. However if you never need to perform under such conditions, why train this?? The consensus seemed to be that it wouldn't hurt to do it every once in a while (maybe a couple times a week). The concern was with glycogen depleting, this being where the problem lies, but obviously under certain durations this is not an issue (and fasting over night only lowers liver glycogen am I right?). Based on the findings in the article you posted I think it could be optimal to do fasted training a couple times a week to reap glycogen storage and fuel efficiency benefits, but also make sure to train unfasted as well in order to reach the intensities/durations needed to improve functions where high glycogen levels are beneficial (like training VO2 max in the blog).

If you're doing sub 2hr. rides and shorter recovery rides in this state I cannot see how it would compromise the quality of your training (it hasn't mine). I've done 45min crits in a fasted state no problem (although I prefer to eat a few hours beforehand). It seems this would be beneficial to road racers as your glycogen levels are destined to reach lower points during long events (since you can't replace as much as you are using).

I also asked about effects on performance regarding longer fasts (such as a water fast that is several weeks in duration). The response was simply that a healthier system returns better performances and adapts to training stress faster/more efficiently.

dingrr
Posts: 3
Joined: Tue Jul 20, 2010 2:25 am

by dingrr

I haven't tried it yet but Mark Sisson believes it is beneficial. Plenty to read out there...

http://www.marksdailyapple.com/fasting/

kevinkalis
Posts: 597
Joined: Tue Aug 03, 2010 6:29 pm

by kevinkalis

Thanks for the link dingrr. I've been trying it for a few weeks now and it doesn't seem like my training has suffered for it.
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fastezzie
Posts: 48
Joined: Fri Jun 30, 2006 9:30 pm

by fastezzie

Hello WW's!
Has anyone here tried the FastDiet (5-2 diet) or similar fasting regimen?
I am looking for information from cyclists and other athletes regarding effects on training and performance.
I stumbled across this article + others:
http://www.scientificamerican.com/artic ... thier-life

Some pretty impressive claims, looks like human trials are still in the early stages though. Might give it a shot myself.

Thanks!

asdf123
Posts: 123
Joined: Mon Sep 24, 2012 12:58 am

by asdf123

I did IF for about 11 months last year.
Although I've had great results with that form of eating it didn't work for my 2 or even 3 sessions of training a day for witch I needed energy to burn and replenish afterwards.
If you train once or twice its great, just build your training window around the eating window or the other way around.
Now I eat when I literally need to eat ea. I have a small session in the morning and a big one in the afternoon? Try doing it fasted then get a meal in after then don't eat till 1-2h before the PM session. Slam a higher carb meal before. After the session get a nice balanced meal.
That's about it. Food is just fuel.

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Cuki
Posts: 63
Joined: Tue Jan 07, 2014 8:20 pm
Location: Vienna

by Cuki

Food is a little more than just fuel. Actually it is a lot more. Food is the most comprehensive form of medicine the human body knows and can deal with. We call these nutrients and you should never deny your body of them. Your body needs them daily, almost hourly actually.

asdf123
Posts: 123
Joined: Mon Sep 24, 2012 12:58 am

by asdf123

No need to quote above

You mean you can't live and hour without supplying your body with some kind of food nutrient?
What I meant by fuel is: I eat it when I need it and when I don't need it I don't eat it witch doesn't deny nutrient intake.
When I feel like I need i.e. magnesium because I flushed it out from my body with hard training I eat some flax or sunflower seeds or take a supplement.
Cause and effect.

by Weenie


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