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2009-10-07 6:53 PM

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Subject: Race Day Fueling video question
I just watched the Race Day Fueling video on the front page of BT, and am perplexed by one of the comments. According to the video, your muscle glycogen stores will be depleted more rapidly if you consume food 1-2 hours prior to the race. Instead, have the pre-race meal at least 3 hours prior, or consume 100-200 easily digested calories just prior to the race.

Why/how does food eaten say 1-2 hours prior to the race deplete muscle glycogen stores??

-Kirk



2009-10-07 7:05 PM
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Subject: RE: Race Day Fueling video question
I just watched the video, and am wondering the same thing! More pertinent for me, would be..is there and reason NOT to eat around 2 hrs before, then top off with 100 cal?
2009-10-07 7:09 PM
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Subject: RE: Race Day Fueling video question
^^I was wondering the same thing. I've been told by an RD that 2 hours before is okay especially for longer events.
2009-10-07 8:51 PM
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Subject: RE: Race Day Fueling video question
Good! Since I am someone who can eat a normal size meal, then head right out the door for a long run.
2009-10-07 9:02 PM
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Subject: RE: Race Day Fueling video question
KirkD - 2009-10-07 7:53 PM I just watched the Race Day Fueling video on the front page of BT, and am perplexed by one of the comments. According to the video, your muscle glycogen stores will be depleted more rapidly if you consume food 1-2 hours prior to the race. Instead, have the pre-race meal at least 3 hours prior, or consume 100-200 easily digested calories just prior to the race. Why/how does food eaten say 1-2 hours prior to the race deplete muscle glycogen stores?? -Kirk


that makes no sense.. they need supporting data to make a claim like that.  All the data out there I've seen suggests that pre/during fueling is glycogen sparing.
2009-10-07 9:27 PM
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Subject: RE: Race Day Fueling video question

Well... the hammer guys do a lot of research, and are well respected.  There is almost undoubtedly some truth to what he's saying. 

But there is no question that he didn't explain at all why his statement was true.

My guess off hand is that it takes energy to digest food.  Do you know the "food coma" from overeating?  That might apply here, but it would certainly seem to depend on what and how much you ate.

....

I went and looked up the answer.  Hammer has a rather technical 100 page book on fueling that you can download from their website.

Here's the full answer.  I can see why he didn't try to explain this in a 5 minute video:

If you consume high glycemic

carbohydrates such as simple sugars

(or even the preferred complex

carbohydrates such as starches and

maltodextrins) within three hours of

exercise, you can expect the following,

with possible negative effects on

performance:


1. Rapidly elevated blood sugar causes

excess insulin release, leading to

hypoglycemia, an abnormally low level

of glucose in the blood.


2. High insulin levels inhibit lipid

mobilization during aerobic exercise,

which means reduced fats-to-fuels

conversion. Our ability to utilize stored

fatty acids as energy largely determines

our performance, which is why we can

continue to exercise when our caloric

intake falls far below our energy

expenditure. We want to enhance,

not impede, our stored fat utilization

pathways.


3. A high insulin level will induce blood

sugar into muscle cells, which increases

the rate of carbohydrate metabolism,

hence rapid carbohydrate fuel depletion.

In simple terms: high insulin means

faster muscle glycogen depletion.


You must complete your pre-race fueling

three or more hours prior to the start

to allow adequate time for insulin and

blood glucose to normalize.



2009-10-07 9:56 PM
in reply to: #2448584

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Subject: RE: Race Day Fueling video question
mrcurtain: Thank you for looking up the details. The description makes sense physiologically and I would suspect that this is for particularly long events - HIM or IM. I wonder if it would actually have an impact on sprint and Oly distances. Nonetheless, proper practice leads to better performance, right?

OK - low glycemic carbs plus some protein 3 hours prior. I would guess that the glycemic index immediately prior to or during the race make little difference since there is a depressed insulin response during exertion. Just enough to push glucose into the cells but not enough to be considered a 'spike'.

Is it any wonder we love physiology so much?

-Kirk

2009-10-07 10:25 PM
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Subject: RE: Race Day Fueling video question
KirkD - 2009-10-07 6:53 PM I just watched the Race Day Fueling video on the front page of BT, and am perplexed by one of the comments. According to the video, your muscle glycogen stores will be depleted more rapidly if you consume food 1-2 hours prior to the race. Instead, have the pre-race meal at least 3 hours prior, or consume 100-200 easily digested calories just prior to the race. Why/how does food eaten say 1-2 hours prior to the race deplete muscle glycogen stores?? -Kirk


While there are studies suggesting carbohydrate (CHO) intake 1 hr prior to exercise causes a rise in plasma insulin concentrations and this suppress the oxidation of fat as fuel which leads to and increase oxidation of muscle glycogen resulting in faster depletion, much more studies suggest that any metabolic interruption after CHO intake 1 hr prior exercise are usually momentary/insignificant (unless you are for instance diabetic)

AFIK subtrate utilization is more a function of exertion intensity, fitness level, personal physiology, duration of session and other variables such as temperature, daily diet, immediate diet pre-exercise (what kind of food you eat, how close to exercising, etc.) hence still having adequate fueling prior to training/racing is important. To avoid what I mentioned above one could avoid consuming CHO during the 1hr window or rely on CHO drinks specially 5-10min before the session, choose low glycemic foods, consume more CHO than usual (though this can produce GI issues), etc.

If for whatever reason I can't fuel withing my usual 3 hr window before racing/training *I* still would rather fuel within 2 or even 1 hr prior just with some adjustments to the quantity and type of fuel (high vs low glycemic) all based on the how hard I expect to race and for how long.


Edited by JorgeM 2009-10-07 10:29 PM
2009-10-08 12:29 PM
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Subject: RE: Race Day Fueling video question
JorgeM - 2009-10-06 11:25 PM To avoid what I mentioned above one could avoid consuming CHO during the 1hr window or rely on CHO drinks specially 5-10min before the session, choose low glycemic foods, consume more CHO than usual (though this can produce GI issues), etc.




by "GI Issues" did you mean: 

Gastro-Intestinal

or


Glycemic Index?
2009-10-08 12:43 PM
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Subject: RE: Race Day Fueling video question
moondawg14 - 2009-10-08 12:29 PM
JorgeM - 2009-10-06 11:25 PM To avoid what I mentioned above one could avoid consuming CHO during the 1hr window or rely on CHO drinks specially 5-10min before the session, choose low glycemic foods, consume more CHO than usual (though this can produce GI issues), etc.




by "GI Issues" did you mean: 

Gastro-Intestinal

or


Glycemic Index?
oops, yes gastro-intestinal.
2009-10-08 1:22 PM
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Subject: RE: Race Day Fueling video question
mrcurtain - 2009-10-07 10:27 PM
Well... the hammer guys do a lot of research, and are well respected.  There is almost undoubtedly some truth to what he's saying. 

But there is no question that he didn't explain at all why his statement was true.

My guess off hand is that it takes energy to digest food.  Do you know the "food coma" from overeating?  That might apply here, but it would certainly seem to depend on what and how much you ate.

....

I went and looked up the answer.  Hammer has a rather technical 100 page book on fueling that you can download from their website.

Here's the full answer.  I can see why he didn't try to explain this in a 5 minute video:

If you consume high glycemic

carbohydrates such as simple sugars

(or even the preferred complex

carbohydrates such as starches and

maltodextrins) within three hours of

exercise, you can expect the following,

with possible negative effects on

performance:


1. Rapidly elevated blood sugar causes

excess insulin release, leading to

hypoglycemia, an abnormally low level

of glucose in the blood.


2. High insulin levels inhibit lipid

mobilization during aerobic exercise,

which means reduced fats-to-fuels

conversion. Our ability to utilize stored

fatty acids as energy largely determines

our performance, which is why we can

continue to exercise when our caloric

intake falls far below our energy

expenditure. We want to enhance,

not impede, our stored fat utilization

pathways.


3. A high insulin level will induce blood

sugar into muscle cells, which increases

the rate of carbohydrate metabolism,

hence rapid carbohydrate fuel depletion.

In simple terms: high insulin means

faster muscle glycogen depletion.


You must complete your pre-race fueling

three or more hours prior to the start

to allow adequate time for insulin and

blood glucose to normalize.



I'll have to pick through the journal I subscribe to, but I believe this is only based upon theory, not actual data.  Digestion takes a long time, so as long as you are still digesting your meal during your workout, spiking insulin immediately prior and during exercise does not have the same effect as it does on resting individuals.  This is based on my memory of the review I read, so I'll come back and post some better links when I can find them. 


2009-10-08 1:46 PM
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Subject: RE: Race Day Fueling video question
http://www.ncbi.nlm.nih.gov/pubmed/14971431?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

I believe this is a review article which covers several studies on immediate (60-90 minutes) pre-event carbohydrate fueling. 
2009-10-08 2:31 PM
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Subject: RE: Race Day Fueling video question
Thanks for the review article link. I need to read the whole article, but from the abstract:


Ingestion of carbohydrate 3-4 h before exercise increases liver and muscle glycogen and enhances subsequent endurance exercise performance. The effects of carbohydrate ingestion on blood glucose and free fatty acid concentrations and carbohydrate oxidation during exercise persist for at least 6 h. Although an increase in plasma insulin following carbohydrate ingestion in the hour before exercise inhibits lipolysis and liver glucose output, and can lead to transient hypoglycaemia during subsequent exercise in susceptible individuals, there is no convincing evidence that this is always associated with impaired exercise performance.


So it seems the jury is possibly out on the actual effect.

This paper also led me to this one: Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise.

From the abstract:

We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO2 peak) cycling exercise, and improves 40 km time-trial performance.

and

Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading.



And this begs the next question, has anyone tried diet modification to induce fat metabolism? And, would it be reasonable to include medium chain triglycerides in drinks such as Heed or Cytomax or even better yet in a gel? MCTs can be metabolized during high exertion activity and would hold off glycogen usage. Is it possible that we're missing a very useful factor here?

-Kirk



Edited by KirkD 2009-10-08 2:38 PM
2009-10-08 3:43 PM
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Subject: RE: Race Day Fueling video question
KirkD - 2009-10-08 3:31 PM Thanks for the review article link. I need to read the whole article, but from the abstract:
Ingestion of carbohydrate 3-4 h before exercise increases liver and muscle glycogen and enhances subsequent endurance exercise performance. The effects of carbohydrate ingestion on blood glucose and free fatty acid concentrations and carbohydrate oxidation during exercise persist for at least 6 h. Although an increase in plasma insulin following carbohydrate ingestion in the hour before exercise inhibits lipolysis and liver glucose output, and can lead to transient hypoglycaemia during subsequent exercise in susceptible individuals, there is no convincing evidence that this is always associated with impaired exercise performance.
So it seems the jury is possibly out on the actual effect. This paper also led me to this one: Nutritional strategies for promoting fat utilization and delaying the onset of fatigue during prolonged exercise. From the abstract:
We have shown that the ingestion of medium-chain triacylglycerols in combination with carbohydrate spares muscle carbohydrate stores during 2 h of submaximal (< 70% VO2 peak) cycling exercise, and improves 40 km time-trial performance. and Dietary fat adaptation for a period of at least 2-4 weeks has resulted in a nearly two-fold increase in resistance to fatigue during prolonged, low- to moderate-intensity cycling (< 70% VO2 peak). Moreover, preliminary studies suggest that mean cycling 20 km time-trial performance following prolonged submaximal exercise is enhanced by 80 s after dietary fat adaptation and 3 days of carbohydrate loading.
And this begs the next question, has anyone tried diet modification to induce fat metabolism? And, would it be reasonable to include medium chain triglycerides in drinks such as Heed or Cytomax or even better yet in a gel? MCTs can be metabolized during high exertion activity and would hold off glycogen usage. Is it possible that we're missing a very useful factor here? -Kirk


Interesting article... I'll link you to the free sample research review from the same source where I get most of my dietary information.  He covers fat adaption and MCT's pre-and during exercise.  While this one study might be supportive of the use, the collection of data doesn't suggest that becoming fat adapted is beneficial, and consuming MCT's during exercise can induce some nasty cramps.

http://alan7218403.110mb.com/AARR%20Jan%202008.pdf
2009-10-08 3:50 PM
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Subject: RE: Race Day Fueling video question
Dang. I thought I had found something good there. 8^) GI distress would certainly not be a good thing to contend with.

I find it interesting that through the review and other papers I've been looking at, they mention that fat adaptation, etc. don't improve performance, but they seem to be doing 20K cycling time trials. Have you seen any research on longer duration events? The way I'm thinking about it is that 20K is not long enough to really get into glycogen depletion similar to what you would see on an HIM or IM. I wonder if glycogen preservation for much longer duration events would show improved performance as ability to maintain a given sub-maximal pace for longer time.

EDIT: The newsletter you linked is fantastic! It actually answers some of the questions I've posited above. Thanks!! It looks like fat is losing out consistently.


Edited by KirkD 2009-10-08 3:57 PM
2009-10-12 5:18 PM
in reply to: #2448584


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Subject: RE: Race Day Fueling video question
Friends -

Due to the volume of emails and other work-related jobs I have at Hammer Nutrition, I may not be able to be as involved in this forum as I'd like to. However, I was recently notified of this particular thread and invited to join the forum. So here I am!

Of all the articles the are contained within the pages of The Endurance Athlete's Guide to Success (http://www.hammernutrition.com/guide), the article "The Pre-Race Meal" (also found on its own at www.hammernutrition.com/za/HNT?PAGE=ARTICLE&ARTICLE.ID=1279) has, by far, generated the most skepticism. However, over the past decade or so, we have received nothing but positive feedback from athletes who have practiced the principles outlined in the article.

Here is some information that I am hopeful you find useful in helping to explain the rationale behind the "no eating for three hours prior" recommendation...

Dr. Bill Misner writes: "Insulin, as the regulatory hormone that determines the fate of exogenous carbohydrate fate for the energy cycle, should only be recruited 3 hours before or a few minutes prior to to exercise. This action practiced will enable the endurance athlete to increase performance by making muscle glycogen stores available longer, resulting in improved performances. Needlessly taking large amounts of insulin-provoking high glycemic carbohydrates sooner than 3 hours before the event only imposes a hormone environment that spends glycogen stores faster than optimal potential."

Another quote of Dr. Misner's that I refer to often (paraphrasing): "Eating carbohydrates sooner than 3 hours prior to the event start will make a significant difference. To the degree insulin levels are elevated at the start of a race, the greater the body spends its muscle glycogen for energy production. The lower the insulin levels at the start of the event, the better your body spares available muscle glycogen stores. In other words, if insulin & blood sugars are elevated at the start of the event, it makes the body 'conclude' its fuel stores are abundant, therefore causing them to be spent less efficiently. This causes a fuel deficit sooner than if the athlete had set the blood sugar thermostat to its' lowest level by fasting 3 hours prior to the event."

It takes many, many weeks of hard training, followed by the ASAP consumption of food or a post-workout recovery drink to accrue those hard-earned minutes of glycogen... why would athletes do anything to negate all that hard work, which they'll definitely do by eating too close to the start of a longer-duration workout or race? In an article that appeared in one of Dr. Misner's issues of "The Journal of Endurance" he writes that carbohydrates taken in sooner than three hours prior to exercise has three less-than-optimal or negative effects on performance. I took that information and rewrote it for inclusion in the article "The Pre-Race Meal" (http://www.hammernutrition.com/za/HNT?PAGE=ARTICLE&ARTICLE.ID=1279)

1.Rapidly elevated blood sugar causes excess insulin release, leading to hypoglycemia, an abnormally low level of glucose in the blood.

2. High insulin levels inhibit lipid mobilization during aerobic exercise, which means reduced fats-to-fuels conversion. Our ability to utilize stored fatty acids as energy largely determines our performance, which is why we can continue to exercise when our caloric intake falls far below our energy expenditure. We want to enhance, not impede, our stored fat utilization pathways.

3. A high insulin level will induce blood sugar into muscle cells, which increases the rate of carbohydrate metabolism, hence rapid carbohydrate fuel depletion.

-- END --

As far as energy expense during exercise, here is a chart I had on file that illustrates where the body, in general, derives its sources of energy at a 30% - 65% effort...

KEY: FA=FATTY ACIDS, BG=BLOOD GLUCOSE, MG=MUSCLE GLYCOGEN

TIME IN MINUTES---------FA----------BG---------MG
0-30'------------------------37%-------27%-------36%
60'--------------------------40%--------30%------30%
120'------------------------48% ------- 34%------20%
180'------------------------50%---------34%------14%
240'------------------------62%---------30%-------8%

As you can see, the body relies heavily on muscle glycogen during the first 60-90 minutes of exercise. After that, the shift leans more towards exogenously supplied carbohydrates, with fatty acid utilization increasing as exercise continues. As listed in #2 above, if you eat too close to the start of a prolonged (90+ minute) workout or race, you inhibit your body's ability to utilize the calories from fatty acids for fuel... in a long-duration event that definitely has performance-inhibiting consequences. Also, as listed in #3 above, if you eat to close to the start of a prolonged workout or race, you  potentially increase the rate at which exogenously-supplied carbohydrates (along with muscle glycogen stores) are metabolized. That too has negative performance consequences.

What's important to note, is that the "no calories for three hours prior" suggestion/recommendation is really only applicable for longer-duration workouts or races, not for shorter-duration exercise (somewhere in the range of 90 minutes or under, though I personally err on the conservative side and generally suggest no more than 60 minutes, perhaps 75 minutes at the longest). The rationale for this is explained in the section of the article entitled "Are there any exceptions to the three-hour rule?" which I've cut and pasted below...

When you're competing in races in the 90-minute range or shorter (personally, I prefer an hour limit), fasting three hours prior to the start of the race is not necessary. Consuming some easily digested calories an hour or two prior to the start will not negatively affect performance, and may actually enhance it. Here's why:

As we've discussed earlier, when you consume calories sooner than three hours prior to the start of a race, you accelerate the rate at which your body burns its finite amounts of muscle glycogen stores. In events lasting longer than 60-90 minutes, refraining from calorie consumption for the three-hour period prior to the start is crucial because you want to preserve your glycogen stores, not accelerate their depletion. Muscle glycogen is the first fuel that the body will use when exercise commences, and your body only has a limited supply of this premium fuel. If your workout or race goes beyond the 60-90 minute mark, you don't want to do anything that will accelerate muscle glycogen utilization. However, when you consume calories within three hours of a race, that's exactly what will happen; you'll increase the rate at which your glycogen is burned.

During shorter distance races, however, accelerated rates of glycogen depletion/utilization are not problematic. You don't need the calories for energy, but the presence of carbohydrates will elevate glycogen utilization. In a short race, that's what you want.

Dr. Misner explains that prior to shorter-duration races, consuming a few easily digested carbohydrates will advance performance, because carbohydrates consumed prior to exercise "make the body super-expend its glycogen stores like a flood gate wide open." In other words, if you eat something 1-2 hours prior to the start of a short-duration race, thus causing the insulin "flood gates" to open, yes, you will be depleting your glycogen stores at maximum rates. However, at this distance it's a beneficial effect, as glycogen depletion is not an issue when the race is over within at most 90 minutes.

Bottom line: Fast three hours prior to the start of a longer-duration event (60-90+ minutes). For shorter events, consuming a small amount of fuel an hour to two prior to the start may enhance performance.

--- END ---

Friends, I realize the "no eating for three hours" suggestion seems highly counterintuitive; in fact, most people are extremely skeptical about giving it a try (I've literally had a few athletes say I'm nuts when it comes to making that suggestion). However, it does make sense physiologically speaking, which Dr. Misner discusses in more science-based detail in the article "The Science Behind The Hammer Nutrition Pre-Race Meal Protocol" at http://www.hammernutrition.com/za/HNT?PAGE=ARTICLE&ARTICLE.ID=2981. If you are seeking scientific supporting data behind the "no calories for three hours prior" suggestion/recommendation, this article will be of particular interest to you.

Again, this is admittedly the fueling suggestion/recommendation that has, by far, generated the most skepticism. However, in the nearly ten years I've been here at Hammer Nutrition (longer for Dr. Misner), I've yet to hear one negative report from an athlete who has applied our suggestions/recommendations in their training and racing. Dr. Misner once wrote a client and said, "When I first wrote this suggestion based on the rationale [stated in the article "The Science Behind The Hammer Nutrition Pre-Race Meal Protocol"], several well-informed endurance athletes questioned this recommendation, including some of our own staff. From those subjects (including several elite athletes) who tried this methodology of pre-exercise nutrition 3 hours prior, 100% reported improved performance."

At any rate, I hope youwill consider giving our pre-exercise/race suggestions a thorough test in their training. You have nothing to lose by testing it out and I have no doubt it can make a noticeably positive impact on the quality of your workouts and in your race performances... it's definitely worth giving an honest and thorough try.

Should anyone have any questions after reading the above-mentioned information, or any of the information in the articles I've listed, they are welcome to email me directly at [email protected]. I'll do my best to reply to you in as timely a fashion as possible.

Most sincerely -

Steve Born
Hammer Nutrition



2009-10-12 5:28 PM
in reply to: #2448584


2

Subject: RE: Race Day Fueling video question
Although I am coming in late on the topic, I did want to share some thoughts on Medium Chain Triglycerides (MCTs). I have not had the opportunity to review all the available research, but from what I can tell, the majority of the studies done have looked at endurance cyclists to determine the effectiveness of MCTs on increasing endurance performance. Researchers have studied both the use of muscle glycogen when MCTs are consumed and the effect that MCTs have on cycling times.

In these studies the endurance cyclists engaged in moderate to intensive exercise while ingesting an MCT supplement, an MCT supplement plus a carbohydrate supplement, or a placebo (an inactive substance). The results of these studies suggest that MCT oil does not reduce the use of muscle glycogen or improve endurance performance.

REFERENCES:

*** Jeukendrup AE. Oxidation of orally ingested medium chain triglyceride (MCT) during prolonged exercise. Med Sci Sport Exerc 27 (Suppl.): S101, 1995.

*** Jeukendrup AE, et al. Effect of medium-chain triacylglycerol and carbohydrate ingestion during exercise on substrate utilization and subsequent cycling performance. Am J Clin Nutr 67: 397-404, Seaton TB, Welle SL, Warenko MK, Campbell RG. 1986. Thermic effect of medium-chain and long-chain triglycerides in man. American Journal of Clinical Nutrition, 1986, 44:630-634.

*** Van Zyl CG, Lambert EV, Hawley JA, Noakes TD, Dennis SC. 1996. Effects of medium-chain triglyceride ingestion on fuel metabolism and cycling performance. Journal of Applied Physiology, 1996, 80:2217-2225.

Dr. Michael Colgan writes that studies using MCTs with healthy, non-obese men and women not on low-fat diets reported that the subjects' fat oxidation increased and protein oxidation was reduced, both good things. The subjects didn't lose weight but the MCTs were burned for energy, which helped to spare muscle tissue. The problem is that for this effect to occur 51% of the diet must come from MCTs and that much fat in the diet, no matter how seemingly beneficial it may be, is too much. In addition, high amounts of MCTs have been known to cause stomach distress in a lot of people.
2009-10-12 5:44 PM
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Subject: RE: Race Day Fueling video question
Steve,

Fantastic responses and thank you for your input! I'm very interested in this topic and will certainly do some research on my own - me being the guinea pig.

One observation: the take home message that I'm getting is that for longer events (over 90 minutes) we want to have a normal, (ie, low) fasting insulin level in order to prevent hyper-usage of glycogen stores and under utilization of fat stores. To what degree does the nutrient mix of the meal come into play? For example, if 1.5 hours prior to an event I take in a couple of gels and a carbohydrate drink, I'm going to get a massive insulin spike which will be problematic. But, what if my nutrient mix were low-glycemic foods along with some fat and protein to blunt the insulin response, such as a couple of eggs and some whole grain bread.

I realize that this comes down to nit picky details, but I'm curious about what is known about mixed nutrient meals in this type of situation.

Thank you again and thank you for the reference links!

-Kirk

2009-10-13 5:45 AM
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Subject: RE: Race Day Fueling video question
KirkD - 2009-10-08 4:50 PM Dang. I thought I had found something good there. 8^) GI distress would certainly not be a good thing to contend with. I find it interesting that through the review and other papers I've been looking at, they mention that fat adaptation, etc. don't improve performance, but they seem to be doing 20K cycling time trials. Have you seen any research on longer duration events? The way I'm thinking about it is that 20K is not long enough to really get into glycogen depletion similar to what you would see on an HIM or IM. I wonder if glycogen preservation for much longer duration events would show improved performance as ability to maintain a given sub-maximal pace for longer time. EDIT: The newsletter you linked is fantastic! It actually answers some of the questions I've posited above. Thanks!! It looks like fat is losing out consistently.


If you like the newsletter, pay the subscription ($10) and you can get access to all of them.  The second one he did has a nice breakdown of pre-during-post carbohydrate and protein intake. 
2009-10-13 9:56 AM
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Subject: RE: Race Day Fueling video question
Bioteknik - 2009-10-13 4:45 AM
If you like the newsletter, pay the subscription ($10) and you can get access to all of them.  The second one he did has a nice breakdown of pre-during-post carbohydrate and protein intake. 





Sounds like a bargain for $10. Thanks!


Edited by KirkD 2009-10-13 9:56 AM
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