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#1
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Carbo Feeds When Training?
A buddy of mine who is a monster endurance athlete used to tell me he
"intuitively" knew that feeding with carbohydrates when training prevented best use of fat for metabolism and trained the body to need carbohydrate. This was about 15 years ago. I just read a summary of a study by Bengt Saltin, said to be a leading sports physician. My buddy's contention is apparently supported. Here's the blurb from http://www.jenex.com/news/index.html.: One of the world's foremost Sports Medicine doctors, Bengt Saltin, who won the IOC Sports Medicine prize in 2002 suspected that training for endurance while using "sports drinks" and power bars might not the best way to develop the body for optimal results in long distance races. ( Of course the sports drinks power bar companies will try to prove him wrong. A well recognized US Researcher told me that the difference between studies in Scandinavia and the US is that in the States many studies are biased because major food and soft drink firms sponsor the studies. The purse strings for sports research in the US are mainly the marketing giants and without the money, no research. In Scandinavia, Universities generally fund the studies. About ten years ago I was indirectly involved with a University study on an exercise product. The manufacturer of the product was convinced the device was an exercise marvel and wanted a University study to back their marketing claims. When the study showed that power walking was more beneficial than their exercise device, the study was not allowed to be presented. The Doctor who performed the study was obviously upset, but the study was funded by the company and he was not allowed to publish it. ) It is well documented that you need maximum carbohydrate loading for long distance races, but what if the body was better able to use both sugar and fat for fuel? Most endurance athletes train using the same sports drinks as when racing. However, Professor Saltin said that a few years ago he began to question this method for training. Since we have more fat deposits for energy than sugar it is important to be able to utilize both energy sources optimally in long distance races. Bengt Saltin suspected that if we train while consuming sugar drinks, the body would have fewer fat burning enzymes. With sugar available, the enzymes are not needed so they don't get developed. Bengt first tested his theory at the University in Copenhagen, then a study was made in Sweden on 18 skiers divided into two groups of nine. In the ski study, which lasted for eight weeks, the two groups trained three times a week for 1.5 hours and on the fourth day for approximately three hours. One group used a well known sports drink while the others drank only water while training and did not take any carbohydrates for at least one hour after training. Prior to the experiment, biopsies were taken on all athletes. After the eight weeks, new biopsies showed that the group that used only water had substantially more important enzymes for the burning of fat. So in race conditions, the water consuming group could better utilize the two available fuel sources, sugar and fat. This month Bengt Saltin is starting a third study of the potential benefits of reduced carbohydrate intake while training for endurance races. Gary (Got Hammer Gel?) Jacobson Rosendale, NY |
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#2
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Carbo Feeds When Training?
You're suggesting that it may not be in our best interest to drink blueberry
juice while skiing ?? Blasphemy ! :^] jw milwaukee |
#3
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Carbo Feeds When Training?
On Wed, 10 Dec 2003 00:46:05 GMT, "Gary Jacobson"
After the eight weeks, new biopsies showed that the group that used only water had substantially more important enzymes for the burning of fat. So in race conditions, the water consuming group could better utilize the two available fuel sources, sugar and fat. These specific findings don't surprise me. But the key question is, which was able to actually go faster? The problem with training on no carbs or low carbs is that the quality of training is reduced. It's hard to workout as intensely. I think there is some value of not relying on sugar all the time in training -- perhaps in certain types of workouts or certain times in workouts (like early in endurance workouts) or even in certain periods of training -- like in a base-building period. Or if trying to lose weight. But if you're not keeping the stores of carbohydrate in your body topped off, you're going to have a hard time training intensely. Which is bad. JT |
#4
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Carbo Feeds When Training?
To follow up JT's remarks, presumably it would be only during long-distance
endurance training that one should forgo using carb drinks and gels etc., not during any long race obviously, or during intensity training. The question might be how long if at all after the endurance training before you're 'allowed' to start stuffing yourself with pasta, or whatever. Clearly a bad idea to say 'never', or you'd be too weak for any intense training. Did the study have some control over what the athletes who didn't take sportsdrinks did in the hour or two after finishing? Best, Peter |
#5
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Carbo Feeds When Training?
Funny, I just yesterday sent an email to an exercise physiologist
about this very topic. Several years ago a coach at Silverstar admonished me for drinking Gatorade on an LSD ski, saying that it predisposed me to using carbohydrate as fuel rather than fat. Everyone I subsequently asked about this gave me a blank stare. Whether that is true or not, I have another question: do we care about using fat for energy for races at which we are almost immediately racing at lactate threshold or higher? Background: Exercise physiologists use various measurements to determine lactate threshold. One of those measurements is the Respiratory Exchange Ratio (RER) which is apparently a good indicator of fuel utilization. RER is the volume of Co2 divided by the volume of O2. We ventilate off different percentages of O2 and Co2 which indicate whether we are using carbohydrate vs fat for fuel. During a stress test, as we approach lactate threshold we increasingly use carbohydrate. Over LT, we are using almost all carbohydrate. So, in races where you are operating at LT or greater, do we even care if our body is predisposed to carbohydrate metabolism, since that is what we're using anyway? Or is there still some small amount of fat utilization going on, any bit of which we want to hang on to? Obviously, for some folks racing 30-50km races, the research might be very relevant since you might be racing at lower than LT and your carbohydrate stores will presumably not last the entire race: you want your body predisposed to using fat whenever it can. I looked up the research by Bengt Saltin (you can too at http://www.ncbi.nlm.nih.gov/entrez). I believe it is this article: Glucose ingestion blunts hormone-sensitive lipase activity in contracting human skeletal muscle. Am J Physiol Endocrinol Metab. 2004 Jan;286(1):E144-50. Epub 2003 Sep 23 Torsten "Gary Jacobson" wrote in message ... A buddy of mine who is a monster endurance athlete used to tell me he "intuitively" knew that feeding with carbohydrates when training prevented best use of fat for metabolism and trained the body to need carbohydrate. This was about 15 years ago. I just read a summary of a study by Bengt Saltin, said to be a leading sports physician. My buddy's contention is apparently supported. Here's the blurb from http://www.jenex.com/news/index.html.: One of the world's foremost Sports Medicine doctors, Bengt Saltin, who won the IOC Sports Medicine prize in 2002 suspected that training for endurance while using "sports drinks" and power bars might not the best way to develop the body for optimal results in long distance races. ( Of course the sports drinks power bar companies will try to prove him wrong. A well recognized US Researcher told me that the difference between studies in Scandinavia and the US is that in the States many studies are biased because major food and soft drink firms sponsor the studies. The purse strings for sports research in the US are mainly the marketing giants and without the money, no research. In Scandinavia, Universities generally fund the studies. About ten years ago I was indirectly involved with a University study on an exercise product. The manufacturer of the product was convinced the device was an exercise marvel and wanted a University study to back their marketing claims. When the study showed that power walking was more beneficial than their exercise device, the study was not allowed to be presented. The Doctor who performed the study was obviously upset, but the study was funded by the company and he was not allowed to publish it. ) It is well documented that you need maximum carbohydrate loading for long distance races, but what if the body was better able to use both sugar and fat for fuel? Most endurance athletes train using the same sports drinks as when racing. However, Professor Saltin said that a few years ago he began to question this method for training. Since we have more fat deposits for energy than sugar it is important to be able to utilize both energy sources optimally in long distance races. Bengt Saltin suspected that if we train while consuming sugar drinks, the body would have fewer fat burning enzymes. With sugar available, the enzymes are not needed so they don't get developed. Bengt first tested his theory at the University in Copenhagen, then a study was made in Sweden on 18 skiers divided into two groups of nine. In the ski study, which lasted for eight weeks, the two groups trained three times a week for 1.5 hours and on the fourth day for approximately three hours. One group used a well known sports drink while the others drank only water while training and did not take any carbohydrates for at least one hour after training. Prior to the experiment, biopsies were taken on all athletes. After the eight weeks, new biopsies showed that the group that used only water had substantially more important enzymes for the burning of fat. So in race conditions, the water consuming group could better utilize the two available fuel sources, sugar and fat. This month Bengt Saltin is starting a third study of the potential benefits of reduced carbohydrate intake while training for endurance races. Gary (Got Hammer Gel?) Jacobson Rosendale, NY |
#6
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Carbo Feeds When Training?
Whether that is true or not, I have another question: do we care about using fat for energy for races at which we are almost immediately racing at lactate threshold or higher? Another question: Do we care about optimizing fat utilization if we are able to consume carbs during races? If we had to race without carbs then we might want to train without carbs. But we're able to have the same sugary drinks and snacks during a race, maybe it's okay to consume them in training. Or even beneficial because we train the body to absorb the carbs while racing? There does seems to be an idea here that the use of carbs makes us more tired from the workout. That's what's interesting. But it sure sounds like it needs a lot more research. Rob Bradlee |
#7
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Carbo Feeds When Training?
Torsten Heycke wrote:
Funny, I just yesterday sent an email to an exercise physiologist about this very topic. Several years ago a coach at Silverstar admonished me for drinking Gatorade on an LSD ski, saying that it predisposed me to using carbohydrate as fuel rather than fat. Everyone I subsequently asked about this gave me a blank stare. Whether that is true or not, I have another question: do we care about using fat for energy for races at which we are almost immediately racing at lactate threshold or higher? From the energy storage point of view it doesn't matter if your race is under 1hour long (normal persons). But don't use fast carbos just before a race so you alters the insulin balance, if not, then you start with low bloodsugar (carbos in the blood) and have a hard time of doing anything more strenuous for a while. When you are away and up to speed then you can start using fast carbos because then your body regulates the bloodsugar level due to the fact that it is consumed as energy by the working muscles and is not stored. Obviously, for some folks racing 30-50km races, the research might be very relevant since you might be racing at lower than LT and your carbohydrate stores will presumably not last the entire race: you want your body predisposed to using fat whenever it can. Precisely, but how many in this group just do 15k and shorter races and have theire ultimate goal to make this short race the best of the seasoon? For me, the shortest race is 40k, but i maybe do one 15k race a year. -- Forward in all directions Janne G |
#8
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Carbo Feeds When Training?
Rob Bradlee wrote:
Whether that is true or not, I have another question: do we care about using fat for energy for races at which we are almost immediately racing at lactate threshold or higher? Another question: Do we care about optimizing fat utilization if we are able to consume carbs during races? If we had to race without carbs then we might want to train without carbs. But we're able to have the same sugary drinks and snacks during a race, maybe it's okay to consume them in training. Or even beneficial because we train the body to absorb the carbs while racing? Saltin had a discussion about this in a seminar that i have on my server (in Swedish), he says that the amount of energy directly derived from the digested food/sportsdrinks by it self can't sustain the bodys needs for more than around 40-50% of Vo2Max. It was a nice thoght Rob but it seams that we aren't equipped with that fast digestive system to support this to any larger extent. The only thing we can do is to "blend" the storaged carbos with digested carbos to some extent. To make things worse, when approaching the Lactate Threshold (LT) the blood starts to diverge from the digestive system to the working muscles to support the high workload and this also lowers the output from it. -- Forward in all directions Janne G |
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