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The following is written by Steve Blechman. I will post Dave Palumbo's response in the following post.
Are carbs "needed". No, your body can make about 100g of glucose per day with 0 glucose intake and once you go into ketosis, then you need even less. The body only has an obligate glucose usage of about 80g of glucose per day.
As far as them only being deleterious to health... I think Dr. Connely is going overboard on this. Is overconsuming carbohydrates a danger to health? absolutely. But carbs have advantages to.
1) they spare amino acids from oxidation... moreso then protein itself to a certain extent. (via inhibiting gluconeogenesis).
2) They have a synergistic effect with amino acids on increasing protein synthesis in muscle. You will not maximize the anabolic response of muscle to amino acids without at least some insulin, it doesn't have to be a ton, but it does have to rise to normal post prandial levels. You can consume all the protein you want, but you never maximize anabolic signaling without at least a slight increase in insulin. Our lab at U of IL has shown this repeatedly (search Layman DK and Garlick PJ on pubmed for protein synthesis lol)
3) Insulin reduces protein degradation via being a powerful inhibitor of the ubiquitin proteasome system which is the main mechanism by which protein degradation occurs in skeletal muscle. So Carbs can enhance synthesis and decrease breakdown... Since net growth = synthesis - degradation I think it's pretty obvious to see that carb helping to increase synthesis and decrease degradation can lead to increased growth.
4) They increase glycogen which can prolong endurance and help prevent fatigue... though this is less clear.
The problem with almost EVERYONE IN THIS INDUSTRY is everybody views things as ALL OR NOTHING. Something is either bad or good, there is no middle ground. This is simply misguided thinking. Anything can be bad if you have too much of it. Yes that includes protein and fat. Fat has been shown to impair insulin signaling & increase insulin resistance when you get it too high as intracellular DAG (diacylglycerols) builds up and affect kinase involved in the insulin signaling pathway... this makes you less insulin sensitive. So should we now say that fat is completely bad? Of course not.
What EVERYONE needs to realize are there are thresholds when dealing with things like protein and carbohydrates. My work centers around trying to find the anabolic thresholds for amino acids in response to meal intake. However several of my lab collegues are looking at trying to find carbohydrate thresholds. You see... at low carbohydrate intake your liver almost completely regulates carb output. As you increase that more starts to appear in the blood stream faster than the liver can regulat the output and so now insulin must dispose of it. However there is a level of carb intake at which insulin will be disposing of it just into muscle tissue and not very much into fat. Then after a certain level of carb intake muscle will not be able to accomodate all of the glucose and adipose must dispose of the rest.
This is the carb theshold that we are interested in...what is the max amount of carbs you can eat at meal to maximize uptake into muscle while minimizing uptake into fat. Obviously it will be very individually dependant on the person, but our lab's reserach will shed a lot of light onto this in the coming years. In the meantime please see our previous collegue's (Jamie Baum) work on the first piece of evidence dealing with this 'carb theshold' theory: http://ajpendo.physiology.org/cgi/co...full/288/1/E86
I didn't listen to Dr. Connelly's segment, but if indeed he said that carbs are just bad in general and they have no beneficial affects then I really believe that is a poor generalization of what really happens metabolically. Are they needed? No. Can they be helpful... most certainly, if used correctly. This ALL OR NOTHING mentality really disturbs me with how often it is tossed around.
-Layne
I don’t know one Olympian that followed a zero carb or no carb diet!!
Ronnie Coleman lived on chicken and rice for his pre-competition diet.
Dorian Yates in a most recent interview said the following, “If I take very low carbohydrates – I can’t walk. So obviously I need more carbohydrates. In the off-season I was on 2,000 grams of carbohydrates a day and 400 – 500 grams getting ready for a contest, and my contest condition was better than most, for sure, so my body fat was very low on 400 grams of carbohydrates.”
The fact of the matter is that based on the scientific research, zero carb diets are not optimal for muscle growth!! Layne Norton (listed above) eloquently mentioned 4 important points based on the literature. The scientific literature also demonstrates that very low carb diets are catabolic by lowering insulin and IGF-1, and also lower anabolic hormones, testosterone, and growth hormone. Plus they raise cortisol like crazy which is a catabolic hormone and increase blood acidity which can also enhance muscle protein breakdown.
The literature has also shown that for exercising muscle depending on protein for glucose (gluconeogenesis) is very undesirable because it raises blood ammonia which can increase muscle fatigue.
Bottom line is that very low carb diets cause muscle fatigue!! How the hell do you expect to preserve and maintain lean body mass during pre-competition dieting if you can’t train hard. High intensity training helps preserve lean body mass during dieting!!
Because of all the misinformation on low carb ketogenic diets, next month MD will have an extensive up-to-date scientific review article on this subject. And of course like all MD scientific articles, it will be backed up by the scientific literature and properly footnoted and referenced.
You will be in for a big surprise!! A most recent study showed that fish and fish oil were undesirable for very low carb diets inhibiting ketogenesis and lipolysis!!
Stay Tuned……
Are carbs "needed". No, your body can make about 100g of glucose per day with 0 glucose intake and once you go into ketosis, then you need even less. The body only has an obligate glucose usage of about 80g of glucose per day.
As far as them only being deleterious to health... I think Dr. Connely is going overboard on this. Is overconsuming carbohydrates a danger to health? absolutely. But carbs have advantages to.
1) they spare amino acids from oxidation... moreso then protein itself to a certain extent. (via inhibiting gluconeogenesis).
2) They have a synergistic effect with amino acids on increasing protein synthesis in muscle. You will not maximize the anabolic response of muscle to amino acids without at least some insulin, it doesn't have to be a ton, but it does have to rise to normal post prandial levels. You can consume all the protein you want, but you never maximize anabolic signaling without at least a slight increase in insulin. Our lab at U of IL has shown this repeatedly (search Layman DK and Garlick PJ on pubmed for protein synthesis lol)
3) Insulin reduces protein degradation via being a powerful inhibitor of the ubiquitin proteasome system which is the main mechanism by which protein degradation occurs in skeletal muscle. So Carbs can enhance synthesis and decrease breakdown... Since net growth = synthesis - degradation I think it's pretty obvious to see that carb helping to increase synthesis and decrease degradation can lead to increased growth.
4) They increase glycogen which can prolong endurance and help prevent fatigue... though this is less clear.
The problem with almost EVERYONE IN THIS INDUSTRY is everybody views things as ALL OR NOTHING. Something is either bad or good, there is no middle ground. This is simply misguided thinking. Anything can be bad if you have too much of it. Yes that includes protein and fat. Fat has been shown to impair insulin signaling & increase insulin resistance when you get it too high as intracellular DAG (diacylglycerols) builds up and affect kinase involved in the insulin signaling pathway... this makes you less insulin sensitive. So should we now say that fat is completely bad? Of course not.
What EVERYONE needs to realize are there are thresholds when dealing with things like protein and carbohydrates. My work centers around trying to find the anabolic thresholds for amino acids in response to meal intake. However several of my lab collegues are looking at trying to find carbohydrate thresholds. You see... at low carbohydrate intake your liver almost completely regulates carb output. As you increase that more starts to appear in the blood stream faster than the liver can regulat the output and so now insulin must dispose of it. However there is a level of carb intake at which insulin will be disposing of it just into muscle tissue and not very much into fat. Then after a certain level of carb intake muscle will not be able to accomodate all of the glucose and adipose must dispose of the rest.
This is the carb theshold that we are interested in...what is the max amount of carbs you can eat at meal to maximize uptake into muscle while minimizing uptake into fat. Obviously it will be very individually dependant on the person, but our lab's reserach will shed a lot of light onto this in the coming years. In the meantime please see our previous collegue's (Jamie Baum) work on the first piece of evidence dealing with this 'carb theshold' theory: http://ajpendo.physiology.org/cgi/co...full/288/1/E86
I didn't listen to Dr. Connelly's segment, but if indeed he said that carbs are just bad in general and they have no beneficial affects then I really believe that is a poor generalization of what really happens metabolically. Are they needed? No. Can they be helpful... most certainly, if used correctly. This ALL OR NOTHING mentality really disturbs me with how often it is tossed around.
-Layne
I don’t know one Olympian that followed a zero carb or no carb diet!!
Ronnie Coleman lived on chicken and rice for his pre-competition diet.
Dorian Yates in a most recent interview said the following, “If I take very low carbohydrates – I can’t walk. So obviously I need more carbohydrates. In the off-season I was on 2,000 grams of carbohydrates a day and 400 – 500 grams getting ready for a contest, and my contest condition was better than most, for sure, so my body fat was very low on 400 grams of carbohydrates.”
The fact of the matter is that based on the scientific research, zero carb diets are not optimal for muscle growth!! Layne Norton (listed above) eloquently mentioned 4 important points based on the literature. The scientific literature also demonstrates that very low carb diets are catabolic by lowering insulin and IGF-1, and also lower anabolic hormones, testosterone, and growth hormone. Plus they raise cortisol like crazy which is a catabolic hormone and increase blood acidity which can also enhance muscle protein breakdown.
The literature has also shown that for exercising muscle depending on protein for glucose (gluconeogenesis) is very undesirable because it raises blood ammonia which can increase muscle fatigue.
Bottom line is that very low carb diets cause muscle fatigue!! How the hell do you expect to preserve and maintain lean body mass during pre-competition dieting if you can’t train hard. High intensity training helps preserve lean body mass during dieting!!
Because of all the misinformation on low carb ketogenic diets, next month MD will have an extensive up-to-date scientific review article on this subject. And of course like all MD scientific articles, it will be backed up by the scientific literature and properly footnoted and referenced.
You will be in for a big surprise!! A most recent study showed that fish and fish oil were undesirable for very low carb diets inhibiting ketogenesis and lipolysis!!
Stay Tuned……
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