Fasting endurance training?

[Ahillock]

What are thoughts about including a few workouts a week where you fast prior to workout (don't eat from after dinner the night before your morning work out)? Should be about 12-14 hours of fasting state. I have read some articles that point to this as being good for endurance training. Any thoughts or experience?

[benzebub]

I'm not an expert but the things I've read online is that it has some effect in boosting your metabolism and "learning" to use stored body fats as nutrition. Most opinions also say that training should be limited to 1 hour, 1,5 hour max.

I do include some fasting endurance rides in my training, but just once in 2-3 weeks, just to give my body some kind of "shock" and snap it out of routine.

[Nefarious86]

Have done it for ages. Works great if you're not doing anything too intense.

[wheelzqc]

What works ? I mean what do you accomplish ? Do you gain power from it ? Lose fat that wouldn't have lost from eating before ?

[Kayrehn]

What works ? I mean what do you accomplish ? Do you gain power from it ? Lose fat that wouldn't have lost from eating before ?

Endurance athletes aim to train the body to employ fat as fuel by doing fasting exercise sessions. Eventually (if done right), the body will continue to burn more proportion of fat as fuel instead of carbohydrate as the intensity goes up, instead of a constant reliance on the latter.

[BikeAnon]

Ahillock, What are your longest events that you are training for?

[53x12]

What are thoughts about including a few workouts a week where you fast prior to workout (don't eat from after dinner the night before your morning work out)? Should be about 12-14 hours of fasting state. I have read some articles that point to this as being good for endurance training. Any thoughts or experience?

Here is a good article on the subject that is worth reading.


RUNNING ON EMPTY: FASTED ENDURANCE TRAINING
http://www.thecliffedge.net/fastedendurance/


Just a few excerpts from it:

Reason 1, Shifting the Crossover Point
Reason 2, Improved 24 Hour Fat Oxidation
Reason 3, Increased V02 Max
Reason 4, Because the East Africans Do It

It is worth reading the whole article, it isn't very long or complicated.

[Lelandjt]

Never thought about it but I do that often and just eat after the ride. Here on Maui you want to get out early to beat the heat and wind and sometimes I just don't feel like eating at dawn. I've got about 3 hours of hard riding in me before I need to eat which happens to be how long it takes to get around the West Side if you average 20mph.

[Ahillock]

Thank you guys. Lots of good information in here. Does anyone else have other articles that are good reads on the subject?

[Snabb]

Thank you guys. Lots of good information in here. Does anyone else have other articles that are good reads on the subject?

http://gih.diva-portal.org/smash/record ... swid=-5258

http://gih.diva-portal.org/smash/get/di ... TEXT01.pdf

According to swedish studies you get higher effect from the trainngsessions if the glycogen stores in your muscles are low, they recommend that you don`t eat before you train in the morning and after excercise don`t eat in 30 mins. Coaches in scandinavia have begun to recommend this to their athletes.

[TheKaiser]

Thank you guys. Lots of good information in here. Does anyone else have other articles that are good reads on the subject?

I don't know if you have dug into past threads here on WW but if you search for "fasted" or "fasting" there are probably a half dozen or so decent threads. Some are pretty extended, so will link to a few good sections below, where the conversation gets really juicy, however it is worth reading through them all if you are really interested in the topic. KWalker seems to have a good bit of knowledge and firsthand experience with the topic, and links to some good articles. You asked about fasting training, not low-carb training, however note that the topic is often intermingled with "low-carb" discussions, and "glycogen depletion" discussions because many of the same metabolic pathways will be involved along with many of the same potential benefits/pitfalls. Essentially, they are just 3 different ways to get the body into a carb depleted state, through fasting (short term restriction), low-carbing (longer term restriction), or extended workout sessions followed by intervals (activity based depletion), so that the stressor (energy demand while in a carb depleted state) will provoke an adaption.

I also recall seeing some great articles on the AIS website (http://www.ausport.gov.au/ais/nutrition ... adaptation) which are valuable in that they are sport focused, as opposed to a lot of the fasting studies out there which are health/weight loss oriented.

In particular, the studies by L.M Burke are interesting in that they seem to find that while you can improve fat burning with fasted training, it can be at the expense of carb burning, so in an effort to boost endurance you will be stealing from your top-end power production. That may be a good tradeoff for some (people doing events 4hrs+), but it suggests that the hype surrounding the "train low (carb) race high (carb)" technique doesn't offer the benefits that proponents claim for shorter events. In other words, it does not allow you to build your fat burning with a lot of fasted training and then add some carb fuel to the mix to supercharge yourself for a hard ride or competition, because your body's ability to utilize that carb fuel will have been compromised if you spend too much time in a carb depleted state.

Some amount carb depleted training has been shown to increase mitochondrial biogenesis though, so for certain people certain people in certain instances it may hold some value.

viewtopic.php?f=8&t=135041&hilit=fasted&start=75
viewtopic.php?f=8&t=119866&hilit=fasted
viewtopic.php?f=8&t=102833&p=877540&hilit=fasted#p877540
viewtopic.php?f=8&t=69049&hilit=fasted
viewtopic.php?f=8&t=81348&p=713162&hilit=fasted#p713162

[KWalker]

What works ? I mean what do you accomplish ? Do you gain power from it ? Lose fat that wouldn't have lost from eating before ?

Endurance athletes aim to train the body to employ fat as fuel by doing fasting exercise sessions. Eventually (if done right), the body will continue to burn more proportion of fat as fuel instead of carbohydrate as the intensity goes up, instead of a constant reliance on the latter.

No, it won't necessarily. What you burn is a multi-factoral combination of your respiratory quotient, overall macronutrient intake, stored glycogen, and percent of vo2 max.

If you eat a diet with mod-high CHO, your respiratory quotient will reflect this and although you may burn marginally more blood lipids during a single bout of exercise, you won't burn any more fat the rest of the day. Moreover, for most people to actually burn more fat, the KJ expenditure of such a ride would be lower than riding even in a fed state, especially if the fed state ride included enough intensity and/or duration to increase post exercise oxygen uptake. Lastly, there have been studies that show that carb deprivation during even lighter steady state exercise actually can increase a reliance on carbohydrate oxidation throughout the day.

For the full benefits one would have to be at or near ketosis long enough to shift r quotient, which takes quite a few days. Some studies show very minor differences in cellular signaling from fasted or low CHO sessions, but low CHO doesn't necessarily mean fasted and nor has anyone tied those adaptations to correlations in fat mass decreases.

[Carcinogent]

What works ? I mean what do you accomplish ? Do you gain power from it ? Lose fat that wouldn't have lost from eating before ?

Endurance athletes aim to train the body to employ fat as fuel by doing fasting exercise sessions. Eventually (if done right), the body will continue to burn more proportion of fat as fuel instead of carbohydrate as the intensity goes up, instead of a constant reliance on the latter.

No, it won't necessarily. What you burn is a multi-factoral combination of your respiratory quotient, overall macronutrient intake, stored glycogen, and percent of vo2 max.

If you eat a diet with mod-high CHO, your respiratory quotient will reflect this and although you may burn marginally more blood lipids during a single bout of exercise, you won't burn any more fat the rest of the day. Moreover, for most people to actually burn more fat, the KJ expenditure of such a ride would be lower than riding even in a fed state, especially if the fed state ride included enough intensity and/or duration to increase post exercise oxygen uptake. Lastly, there have been studies that show that carb deprivation during even lighter steady state exercise actually can increase a reliance on carbohydrate oxidation throughout the day.

For the full benefits one would have to be at or near ketosis long enough to shift r quotient, which takes quite a few days. Some studies show very minor differences in cellular signaling from fasted or low CHO sessions, but low CHO doesn't necessarily mean fasted and nor has anyone tied those adaptations to correlations in fat mass decreases.

I can add here that to enter ketosis you need something like 4-6weeks. Basically you eat less than 50g of carbs/day and avoid the fast absorbed ones (that cause a huge insulin spike) Than you rely predominanlty on fat while staying in your maximum aerobic zone or the MAF zone. (More info here: http://www.thetallcyclist.com/2015/10/m ... r-cycling/). You need to train at that zone to get the full benefits.

One problem with fasting is that since we are hardwired for survival any signal that food is not readily available is interpreted as stress. If you are already fat adapted/in ketosis there is no real need to go into such lengths as to do fasted workouts (you burn predominantly fat anyway) - you would only be adding extra stress. You can read here what bad stuff any kind of stress does to the body: (http://www.thetallcyclist.com/2016/03/s ... ce-sports/)

[KWalker]

http://road.cc/content/feature/138083-f ... ths-busted

The article is somewhat related, but points out the math behind the fact that the ROI on such methods is extremely low. The amount of extra fat you might oxidize is miniscule at best.

Fasted endurance training also increases cortisol. Low carb training has also been found to decrease RMSSD and have negative vagal functions on the heart. Not dangerous, but increases recovery burden.

People also need to realize that fat oxidation does not necessarily mean fat from adipose tissue.

[gryfon]

I have been reading a lot about this lately....

Some good articles here.... http://www.optimumnutrition4sport.com

One of the main points being that it takes months and months if not years to refine the pathways in the body to work differently.

I'm only riding purely for commuting to work and pleasure, so I have decided to give this method, along with cold exposure (cold thermo genesis) and a LCHF (low carb high fat) lifestyle, a bash and see how I get on. It feels to me like a completely different approach to life