Workout on an empty stomach?

[2LAP]

Originally posted by Roadie_scum
Can I just reiterate that I'm not advocating training on an empty stomach for weight loss also. It is exclusively to train lipolytic metabolism specifically for endurance athletes, and it's training that needs to be completed at pretty low intensities.

I also don't advocate training on an empty stomache to enhance lipid metabolism for a number of reasons...

1. All aerobic training produces favourable adaptations in lipid metabolism and these adaptations might be greatest at higher intenisties where the RATE of lipid metabolism is maximised. Full fueling would be needed.

2. The adaptations that will allow a greater RATE of lipid metabolism are those that allow greater aerobic metabolism (i.e. adaptations that promote oxygen uptake). A clear example of this is that fitter people metabolise lipids at a greater rate and in greater amounts than less fit people when performing at the same absolute or reletive intensity. This is independant of full/empty stomache status.

3. The adaptations in (2) may be acheived most at higher intensities. Which would require full fueling.

4. Why would the metabolic enhancements acheived at low intensities transfer to high intensity race specific situations and therefore benefit athletes? Also training on an empty stomache is unspecific given that during races people will be well fueled. Training on an empty stomache will be low quality and may be difficult to recover from.

5. Given that lipid metabolism isn't a characteristic that limits performance in many cyclists why dedicate a day or more to training it specificaly? While a higher rate of lipid metabolism may spare glycogen, I don't see this as a valid reason given that cyclists are able to consume more carbs during ride or race.

6. Training to increase lipid metabolism is difficult to measure; how do you know when you have improved and how would you define improved (or when the maximum improvement is acheived)? Not everyone (infact not many) has access to gas analysis equipment to estimate lipid metabolism using indirect calorimetry and RER.

I'm not against low intensity training (I'm a big fan of recovery rides); rather just training on an empty stomache even at low intensities with the specific purpose of increasing lipid metabolism. In my mind this is wasted training because (1) its perhaps not the most effective way of getting the desired effects and (2) its unlikely to enhance endurance performance.

 

[ric_stern/RST]

Originally posted by 2LAP
I also don't advocate training on an empty stomache to enhance lipid metabolism for a number of reasons...

1. All aerobic training produces favourable adaptations in lipid metabolism and these adaptations might be greatest at higher intenisties where the RATE of lipid metabolism is maximised. Full fueling would be needed.

2. The adaptations that will allow a greater RATE of lipid metabolism are those that allow greater aerobic metabolism (i.e. adaptations that promote oxygen uptake). A clear example of this is that fitter people metabolise lipids at a greater rate and in greater amounts than less fit people when performing at the same absolute or reletive intensity. This is independant of full/empty stomache status.

3. The adaptations in (2) may be acheived most at higher intensities. Which would require full fueling.

4. Why would the metabolic enhancements acheived at low intensities transfer to high intensity race specific situations and therefore benefit athletes? Also training on an empty stomache is unspecific given that during races people will be well fueled. Training on an empty stomache will be low quality and may be difficult to recover from.

5. Given that lipid metabolism isn't a characteristic that limits performance in many cyclists why dedicate a day or more to training it specificaly? While a higher rate of lipid metabolism may spare glycogen, I don't see this as a valid reason given that cyclists are able to consume more carbs during ride or race.

6. Training to increase lipid metabolism is difficult to measure; how do you know when you have improved and how would you define improved (or when the maximum improvement is acheived)? Not everyone (infact not many) has access to gas analysis equipment to estimate lipid metabolism using indirect calorimetry and RER.

I'm not against low intensity training (I'm a big fan of recovery rides); rather just training on an empty stomache even at low intensities with the specific purpose of increasing lipid metabolism. In my mind this is wasted training because (1) its perhaps not the most effective way of getting the desired effects and (2) its unlikely to enhance endurance performance.

additionally, it's worth simply noting that as you become fitter (i.e. increases in VO2 max, LT) more of the work that you do is covered by fat oxidation, thus training harder is better than easier (obviously, there's a whole bunch of caveats to that)

furthermore, underperforming is often associated with mild/moderate and high levels of glycogen depletion. It's thus important for (specifically) people who race to keep their glycogen levels 'topped' up. if you eat suffiently well enough (moderately high carbohydrate intake) you can maintain and increase glycogen storage.

ric

 

[2LAP]

Originally posted by ricstern
additionally, it's worth simply noting that as you become fitter (i.e. increases in VO2 max, LT) more of the work that you do is covered by fat oxidation, thus training harder is better than easier (obviously, there's a whole bunch of caveats to that)

Thanks Ric

That's the point I was making in (2). The fitter you are the higher the lipid metabolism and lower the carbohydrate metabolism at any intensity.

 

[ric_stern/RST]

Originally posted by 2LAP
That's the point I was making in (2).

errrr... hadn't drunk enough espresso when i wrote that.

ric

 

[2LAP]

Originally posted by ricstern
furthermore, underperforming is often associated with mild/moderate and high levels of glycogen depletion.
ric

Any decent refs on this Ric?

 

[ric_stern/RST]

Originally posted by 2LAP
Any decent refs on this Ric?

I was thinking of something i read in "Science and cycling: current knowledge and future directions for research" Atkinson, Davison, Jeukendrup, and Passfield (JSS, 2003). that high carb intake (7 - 10g/kg bodymass/day results in optimal performance.

there was also some stuff i was reading in relation to overtraining and lack of CHO intake, but i can't recall the refs for that.

ric

 

[Roadie_scum]

Originally posted by ricstern
I was thinking of something i read in "Science and cycling: current knowledge and future directions for research" Atkinson, Davison, Jeukendrup, and Passfield (JSS, 2003). that high carb intake (7 - 10g/kg bodymass/day results in optimal performance.

there was also some stuff i was reading in relation to overtraining and lack of CHO intake, but i can't recall the refs for that.

ric

Can I just make the point that I'm not suggesting a low CHO (or even low calorie) diet. I'm interested in your arguments against low intensity training, and against specifically training lipid metabolism, and I'd love more refs about that. However, I don't think missing breakfast on one day for a specific reason makes for a low carb or low calorie diet. Especially when you then eat properly on the bike and maintain a reasonably low intensity. I know you guys are against doing this too, but I think if you're going to come up with studies they should be about that, not about low CHO intake, which I'm not advocating anyway (actually I'm not advocating anything really... this is all very interesting... thanks for your input peeps).

Also, why do you say

'lipid metabolism isn't a characteristic that limits performance in many cyclists'?

It seems to me that the greater the amount of power one can generate from lipid metabolism, the more you can spare glycogen, and also avoid lactic acid accumulation. Am I missing something drastic here?

 

[Roadie_scum]

Originally posted by 2LAP
I also don't advocate training on an empty stomache to enhance lipid metabolism for a number of reasons...

1. All aerobic training produces favourable adaptations in lipid metabolism and these adaptations might be greatest at higher intenisties where the RATE of lipid metabolism is maximised. Full fueling would be needed.

OK, I accept this, but for how long are you able to get these adaptions. It seems to me the literature tends to favour things which yield a short term gain - it's easier to measure and easier to find participants. My guess would be there are potential benefits that get missed in lower intensity training because longer term adaptions achieved with low intensity are harder to study, and large short term adaptions are best achieved with high intensity, although most athletes will be unable to sustain this type of training for the long term (or will stop getting such a benefit out of it that's why we periodise, no?)

2. The adaptations that will allow a greater RATE of lipid metabolism are those that allow greater aerobic metabolism (i.e. adaptations that promote oxygen uptake). A clear example of this is that fitter people metabolise lipids at a greater rate and in greater amounts than less fit people when performing at the same absolute or reletive intensity. This is independant of full/empty stomache status.

Am I reading correctly here that you are saying lipid metabolism is somehow correlated with fitness, and then arguing that it isn't actually important to most cyclists later on? Perhaps it's independent of full/empty stomach status, but I think we're both begging the point here - neither of us have much evidence on the actual question at hand. Metabolic processes are clearly affected by intake of food with different GI status (for example), you're saying there is absolutely no chance whatsoever that eating nothing close to a ride before hormonal responses are suppressed by exercise then eating once exercise is underway will affect metabolism in some way? Or are you just saying that the correlation between fitness and raised lipid metabolism at a given intensity holds independent of full/empty stomach, which again seems to beg the question?

3. The adaptations in (2) may be acheived most at higher intensities. Which would require full fueling.

I agree with you that higher intensities will require full fuelling - see (1) re higher intensities.

4. Why would the metabolic enhancements acheived at low intensities transfer to high intensity race specific situations and therefore benefit athletes?

Because not all of a road race is high intensity. Because Jacky Durand needs to rely on a fair bit of lipid metabolism once he's established his break at the start (though he'd need a whole lot of other well trained energy systems to get away from the bunch in the first place) - so would ironman triathletes.

Also training on an empty stomache is unspecific given that during races people will be well fueled. Training on an empty stomache will be low quality and may be difficult to recover from.

It may be specific to improving a certain energy system, it may not. I don't think this really answers the question, more assumes the answer - the specificity argument can only be applied once you've established a lack of correlation between athletic performance and lipid metabolism, or a lack of correlation between the kind of training I'm suggesting and improvements in lipid metabolism.

5. Given that lipid metabolism isn't a characteristic that limits performance in many cyclists why dedicate a day or more to training it specificaly? While a higher rate of lipid metabolism may spare glycogen, I don't see this as a valid reason given that cyclists are able to consume more carbs during ride or race.

Why do you say it isn't a characteristic that limits many cyclists? Because it is difficult to measure?

6. Training to increase lipid metabolism is difficult to measure; how do you know when you have improved and how would you define improved (or when the maximum improvement is acheived)? Not everyone (infact not many) has access to gas analysis equipment to estimate lipid metabolism using indirect calorimetry and RER.

A lot of things are difficult to measure - it doesn't mean they're not worth doing.

I'm not against low intensity training (I'm a big fan of recovery rides); rather just training on an empty stomache even at low intensities with the specific purpose of increasing lipid metabolism. In my mind this is wasted training because (1) its perhaps not the most effective way of getting the desired effects and (2) its unlikely to enhance endurance performance.

(1) Perhaps... what's your view of periodisation and introduction of intensity? (2) Still interested, think there's more to be said here...

 

[2LAP]

Originally posted by Roadie_scum
Can I just make the point that I'm not suggesting a low CHO (or even low calorie) diet. I'm interested in your arguments against low intensity training, and against specifically training lipid metabolism, and I'd love more refs about that. However, I don't think missing breakfast on one day for a specific reason makes for a low carb or low calorie diet. Especially when you then eat properly on the bike and maintain a reasonably low intensity. I know you guys are against doing this too, but I think if you're going to come up with studies they should be about that, not about low CHO intake, which I'm not advocating anyway (actually I'm not advocating anything really... this is all very interesting... thanks for your input peeps).

Hay roadie (great name by the way); Ric and I went off topic a little and while we weren't talking about a low carb diet either, we were talking about performing with moderate/low glycogen stores. Anyway, back on topic.

Originally posted by Roadie_scum
Also, why do you say

'lipid metabolism isn't a characteristic that limits performance in many cyclists'?

It seems to me that the greater the amount of power one can generate from lipid metabolism, the more you can spare glycogen, and also avoid lactic acid accumulation. Am I missing something drastic here?

Great point... however lipid metabolism isn't something that seperates riders at the end of a race. When talking about glycogen sparing; I think that the amount you can raise lipid metabolism isn't significant enough and eating on the bike has a greater effect on glycogen sparing than raising lipid metabolism through specific training. As for avoiding lactic acid accumulation, other factors are more improtant than lipid metabolism.

 

[2LAP]

Remembering the original point of my post and the training you were advocating (i.e. I don't think that training on an empty stomach is a great way of increasing/training lipid metabolism or will enhance performance) please see below...

Originally posted by Roadie_scum
OK, I accept this, but for how long are you able to get these adaptions. It seems to me the literature tends to favour things which yield a short term gain - it's easier to measure and easier to find participants. My guess would be there are potential benefits that get missed in lower intensity training because longer term adaptions achieved with low intensity are harder to study, and large short term adaptions are best achieved with high intensity, although most athletes will be unable to sustain this type of training for the long term (or will stop getting such a benefit out of it that's why we periodise, no?)

I think you've moved onto a different topic. If we stick with training on an empty stomach; both the low intensity and high intensity training you describe above would have more effect on lipid metabolism (and fitness) than a single or series of empty stomach sessions.

There are perhaps some good questions for another thread in that post.

Originally posted by Roadie_scum
Am I reading correctly here that you are saying lipid metabolism is somehow correlated with fitness, and then arguing that it isn't actually important to most cyclists later on? Perhaps it's independent of full/empty stomach status, but I think we're both begging the point here - neither of us have much evidence on the actual question at hand. Metabolic processes are clearly affected by intake of food with different GI status (for example), you're saying there is absolutely no chance whatsoever that eating nothing close to a ride before hormonal responses are suppressed by exercise then eating once exercise is underway will affect metabolism in some way? Or are you just saying that the correlation between fitness and raised lipid metabolism at a given intensity holds independent of full/empty stomach, which again seems to beg the question?

Again staying on the original topic. Fitness rather than when you last ate will have a more significant and meaningful effect on lipid metabolism.

I am simply saying... if you want to increase lipid metabolism get fit and don't ride on an empty stomach.

Originally posted by Roadie_scum
Because not all of a road race is high intensity. Because Jacky Durand needs to rely on a fair bit of lipid metabolism once he's established his break at the start (though he'd need a whole lot of other well trained energy systems to get away from the bunch in the first place) - so would ironman triathletes.

And would this characteristic be best acheived with empty stomach low intensity rides? Unlikely.

Originally posted by Roadie_scum
It may be specific to improving a certain energy system, it may not. I don't think this really answers the question, more assumes the answer - the specificity argument can only be applied once you've established a lack of correlation between athletic performance and lipid metabolism, or a lack of correlation between the kind of training I'm suggesting and improvements in lipid metabolism.

It doesn't matter if the rate or absolute amount of lipid metabolism is correlated with performance, because a correlation doesn't imply causality (i.e. trained people will have increased lipid metabolism over untrained people; but lance armstrong DIDN'T win the tour de france because he has a high lipid metabolism). Your training (i.e. empty stomach and low intensity) will no doubt increase lipid metabolism as it is aerobic training, but only if there is a great enough stimulous for adaptation.

But for me as a coach the more important questions are; (1) why do your empty stomach form of training if others will acheive same goal faster with different training and (2) why bother specificaly targeting lipid metabolism when it is unlikely to have a significant effect on either peak power output or average power output?

Originally posted by Roadie_scum
Why do you say it isn't a characteristic that limits many cyclists? Because it is difficult to measure?

Its not a limiting factor simply because its difficult to measure; but because aerobic exercise is limited by VO2 max, LT, efficiency/economy and oxygen uptake kinetics. Lipid metabolism doesn't limit any of these factors and as such isn't a limiting factor in cycling (in normal people).

Originally posted by Roadie_scum
A lot of things are difficult to measure - it doesn't mean they're not worth doing.

Measurement is an issue for all training, not just an empty stomach session. And while being unable to measure something doesn't mean its not worth doing, being unable to measure something creates problems that must be recognised.

Even in the lab; lipid metabolism is difficult to measure directly and a ratio of CO2 to O2 is used to estimate this. Measurement is an issue for all training sessions because (1) how do you know its working, (2) how do you know when you have done enough and (3) how do you know the training has had a positive (and not negative) effect.

In short, I don't think specific lipid metabolism training is worth doing.

Originally posted by Roadie_scum
(1) Perhaps... what's your view of periodisation and introduction of intensity? (2) Still interested, think there's more to be said here...

(1) Worlds biggest fan of periodisation and I think that traditionaly UK cyclists do too much volume and not enough intensity.
(2) Neither boosting lipid metabolism or empty stomach training is likely to enhance endurance performance.