Low Carb diet and athletes

[blueriversam]

I tend to be a very passionate person about my beliefs, so I ended up in a screaming match in a restaurant with this friend of mine who was a professional xc ski racer and endurance road biker most of his life. He is also a rheumatologist, so I'm assuming he has some knowledge of biochemistry, although he admitted that chemistry was his weakness in school.

In any case, he argued that in order to do an endurance sport [ie, like the Tour de France], you need *increased* carbohydrates. I was trying to argue that fat and protein were more important, but I think we were both failing at our arguments.

In a side note, I convinced another friend of mine last summer to go on a low carb diet. I told him not to race for a couple of weeks, but he did anyways, and he ended up bonking [basically, just your body shuts down--it's happened to me and carbs are the LAST thing you should eat, I ate a big ice cream and a couple of slices of pizza and I thought I was going to fall on the floor and die] after 20 miles [it was a 50 mile, mostly uphill race and he does a lot of 100-300mi races, so this should be nothing]. He was really sticking to between 15-25g ECC per day and taking all his supplements--K, Mg, Ca, antioxidants, fish oil.

So, I guess my question is, what is the BEST combination of nutrition for endurance athletes? I remember reading about endurance xc skiers who eat nothing but pure animal fat with some protein. I personally feel my strongest and least tired when I am super low carb for a week. However, I think it is very difficult to get over the initial stage while you are trying to train for a big race. Most of the people I know who are pro endurance athletes eat a TON of carbs. If you train 8 hours/day, what would be the difference, would it make a difference, if you ate increased carbs--so long as you eat enough protein?

[protein-girl]

What a great post! I'm looking forward to reading the replies because I also have these questions and arguements with friends. Like you my experience is that the majority of endurance athletes I meet "carbo load" and replace fluids with a combination of water, carbs and protein.

I could be wrong - but I'm starting to believe that there is some role for carbothydrate replacement during endurance events... at least minerals and so on that are lost during enduro need to be replaced (like magnesium).... training on the other hand for eight hours a day ... wow ... I think that anyone training this much would need to increase their energy intake overall, and therefore their carbs and protein.

Anyway I look forward to hearing from the experts ....
PG

[Zedgirl]

Hi, this is my first post on the PP forums but I'm a long time lurker (Hi Malcolm). Protein-girl do I know you?:)

Art De Vany is blogging on this topic at the moment. Thought it might be of interest.

http://www.arthurdevany.com/archives/evolutionary_fitness/index.html

[Gabriel Guzman]

I tend to be a very passionate person about my beliefs, so I ended up in a screaming match in a restaurant with this friend of mine who was a professional xc ski racer and endurance road biker most of his life. He is also a rheumatologist, so I'm assuming he has some knowledge of biochemistry, although he admitted that chemistry was his weakness in school.

In any case, he argued that in order to do an endurance sport , you need *increased* carbohydrates.


So, he doesn't really know about biochemistry. That much is clear.


I was trying to argue that fat and protein were more important, but I think we were both failing at our arguments.

In a side note, I convinced another friend of mine last summer to go on a low carb diet. I told him not to race for a couple of weeks, but he did anyways, and he ended up bonking after 20 miles [it was a 50 mile, mostly uphill race and he does a lot of 100-300mi races, so this should be nothing]. He was really sticking to between 15-25g ECC per day and taking all his supplements--K, Mg, Ca, antioxidants, fish oil.

What most people trying to understand or argue in this regard is that adapation is just as important as the actual food you take. Stephen Phinney described studies conducted on professional (trained) bicyclists as well as untrained individuals (these didn't ride a bike but exercised on a treadmil) and their performance under a very low carbohydrate diet. Their performace decrease during the first weeks, as expected, but it recover after about 4-6 weeks on what they call a 'ketogenic diet' which is strictly speaking a very low carbohdyrate diet (no downtime in training); their performance (i.e. endurance) even increased after that.

This is, at a glance, how the studies were conducted:

Stephen D Phinney. Ketogenic diets and physical performance. [I]Nutrition & Metabolism 2004, 1:2 (emphasis is mine)

This second study utilized competitive bicycle racers as subjects, confined to a metabolic ward for 5 weeks. In the first week, subjects ate a weight maintenance (eucaloric) diet providing 67% of non-protein energy as carbohydrate, during which time baseline performance studies were performed. This was followed by 4 weeks of a eucaloric ketogenic diet (EKD) providing [b]83% of energy as fat, 15% as protein, and less than 3% as carbohydrate (this is as close to the Inuit diet as it gets). The meat, fish, and poultry that provided this diets protein, also provided 1.5 g/d of potassium and was prepared to contain 2 g/d of sodium. These inherent minerals were supplemented daily with an additional 1 g of potassium as bicarbonate, 3 grams of sodium as bouillon, 600 mg of calcium, 300 mg of magnesium, and a standard multivitamin.

And at a glance, what they observed (I'll write here only the part regarding the bicyclists):

S.D. Phinney. Nutrition & Metabolism 2004, 1:2 (emphasis is mine)

The bicyclist subjects of this study noted a modest decline in their energy level while on training rides during the first week of the Inuit diet, after which subjective performance was reasonably restored except for their sprint capability, which remained constrained during the period of carbohydrate restriction. On average, subjects lost 0.7 kg in the first week of the EKD, after which their weight remained stable. Total body potassium (by 40K counting) revealed a 2% reduction in the first 2 weeks (commensurate with the muscle glycogen depletion documented by biopsy), after which it remained stable in the 4th week of the EKD. These results are consistent with the observed reduction in body glycogen stores but otherwise excellent preservation of lean body mass during the EKD (this is one of the risks of neglecting the nutritional part in which protein intake is a key component.

The endurance exercise test on the cycle ergometer was performed at 65% of VO2max, which translates in these highly trained athletes into a rate of energy expenditure of 960 kcal/hr. At this high level of energy expenditure, it is notable that the second test was performed at a mean respiratory quotient of 0.72, indicating that virtually all of the substrate for this high energy output was coming from fat. This is consistent with measures before and after exercise of muscle glycogen and blood glucose oxidation, which revealed marked reductions in the use of these carbohydrate-
derived substrates after adaptation to the EKD.

Examining the results of these two ketogenic diet performance studies together indicates that both groups experienced a lag in performance across the first week or two of carbohydrate restriction, after which both peak aerobic power and sub-maximal (60–70% of VO2max) endurance performance were fully restored. In both studies, one with untrained subjects and the other with highly trained athletes who maintained their training throughout the study, there was no loss of VO2max despite the virtual absence of dietary carbohydrate for 4–6 weeks. This whole-body measure of oxidative metabolism could not be maintained unless there was excellent preservation of the full complement of functional tissues including skeletal muscle (and mitochondrial) mass, circulating red cell mass, and cardiopulmonary functions.


For endurance sports, the food is important but so it to train for it not just to expect that a change in food will accomplish everything. In the case of the cyclists, their bodies had to adapt to the new diet and their performance did not decrease after a period of adaptation was allowed.

Phinney identifies three factors that are important in the context of performance and low carbohdyrate diets (in this context, a low carbohydrate diet is equated to a ketogenic diet, which is indeed a very low carb diet); 1) Adaptation, 2) Sodium and Potasium intake and 3) Protein doese (i.e. protein intake).


So, I guess my question is, what is the BEST combination of nutrition for endurance athletes? I remember reading about endurance xc skiers who eat nothing but pure animal fat with some protein. I personally feel my strongest and least tired when I am super low carb for a week. However, I think it is very difficult to get over the initial stage while you are trying to train for a big race. Most of the people I know who are pro endurance athletes eat a TON of carbs. If you train 8 hours/day, what would be the difference, would it make a difference, if you ate increased carbs--so long as you eat enough protein?

I think a quote from Phinney's conclusions helps with this question...

S.D. Phinney Nutrition & Metabolism 2004, 1:2 (emphasis is mine)

Both observational and prospectively designed studies support the conclusion that submaximal endurance performance can be sustained despite the virtual exclusion of carbohydrate from the human diet. Clearly this result does not automatically follow the casual implementation of dietary carbohydrate restriction, however, as careful attention to time for keto-adaptation, mineral nutriture, and constraint of the daily protein dose is required.


What interests me is that the studies that have shown no decrese in performance after allowing for a period of adaptation have never been refuted, only dismissed on the basis of 'not possible because is not what we've been told...' But the data is there and is solid. The take-home message: adaptation.

It would seem that to perform decenly, your training should combine not only the change in the diet with enough time for adaptation but also the way you train as well. If what Phinney and other people have observed is really what happens, a couple of weeks or even 4 weeks is not enough time for the body to completely shift to a different mode. Nobody really has studied with accuracy how long really takes but certainly, such adaptation doesn't occur in two weeks. The studies pointed out by Phinney present results after 4-6 weeks but ithere may still be some adaptation after that. The point is that after 6 weeks, the subjects' performance was restored and even increased (with the clear exception of the sprint which is glycogen dependent). In other words, besides perhaps the preparation for the big race should start with enough anticipation so adaptation is complete, making sure that the other two factors (mineral balance and protein intake) are equally optimized.

The 'carbs are indispensable to maintain endurance' mind set is becoming another myth of 'low-carb' diets, and it will take some time before the experts dig into the data to understand it.

Phinney's article can be found and downloaded from the Important Links and Resources (http://72.32.36.211/forum/showthread.php?t=68) forum of this board should you also like to enjoy more deails of this fascinating (an enlightening) review.

[Gabriel Guzman]

Hi, this is my first post on the PP forums but I'm a long time lurker (Hi Malcolm). Protein-girl do I know you?:)

Art De Vany is blogging on this topic at the moment. Thought it might be of interest.

http://www.arthurdevany.com/archives/evolutionary_fitness/index.html


An interesting blog. I've read the articles mentioned (and other ones) about glycogen depletion in order to increase endurance. Under a carbohydrate controlled diet, muscle glycogen depletion is really quite easily achieved because there isn't much of it to begin with. In the context of resistance training, that also means that attemping to complete the workout anaerobically (i.e. heavier weights, which required the production of energy quickly) is likely to be a disappointment.

Since here we discussed everything in relation to Protein Power, it's good to put all this scientific in that context as well. When we talk about resistance training together with the nutritional plan itself to help in weight loss, we emphasize the need to train more aerobically rather than anaerobically. Why? because we want to maximize the use of fat and fat can't be used anaerobically... it needs oxygen to be 'burned'! That also means stimulating muscles to work more aerobically, which is perfectly possible even lifting weights and not just spending hours on a treadmil.

So, research tells us that glycogen depletion is needed to trigger all those changes including improved maximal oxygen uptake, prolonged time until exhaustion at a given workload, all that to that allow for greater performance. Fine, but how do you do that? (This thread will likely be linked to the Use it or Lose it forum!).

So... how do you do that? One way would be to start your training focused on trying to deplete your glycogen levels. Of course, it's impossible to have 'zero glycogen' but by 'depletion' we need to undersand 'low enough so the cells are incapable of using it for quick production of energy'. Even on maximum dependence of fat as fuel, we always have 'the last drop' of glycogen that can be used in a situation of emergency to produce a burst of energy which long, long time ago meant the difference between being hunter or prey!

A plausible way to reach leave glycogen levels 'low enough' is to start a training session with heavier loads (of course after proper warm-up) which will require more energy produced quickly, and then continue with ligher weights. Not only the first sets with heavier workloads will use more glycogen but will also trigger the release of that little spit of growth hormone that will in turn trigger the release of another powerful hormone (which is not insulin!) that will drive muscle protein synthesis for the rest of the day and up to 20+ hours after the workout session.

Don't you just like when science makes a lot of sense when you can actually apply it?;)

[mcsblues]

Hi, this is my first post on the PP forums but I'm a long time lurker (Hi Malcolm). Protein-girl do I know you?:)

Art De Vany is blogging on this topic at the moment. Thought it might be of interest.

http://www.arthurdevany.com/archives/evolutionary_fitness/index.html

Hi ZG! About time you stopped lurking. If you hadn't guessed PG = CK. Oh, and you have probably also realised that the Aussies are taking over this forum by stealth and treachery, but it's a big secret, so don't tell anyone, OK?:p

[protein-girl]

Hi Zed and Malcolm... hey what gave it away :) ...

great link Zed... very interesting read

I really like what you are saying gabriel ... I've read the research. I think this is one of those myths that I'm finding the most challenging to get my head around.

PG

[Gabriel Guzman]

I really like what you are saying gabriel ... I've read the research. I think this is one of those myths that I'm finding the most challenging to get my head around.

PG

Probably the most challenging aspect of this plan is to unlearn all we think we've learned in the past about nutrition and other things related to it... exercise being one of the most important ones.

Perhaps what makes it easier for me is that I approach these things from the factual perspective even though I have my own annectdote to convince myself but that, as we all know, that can become too subjective at times. When the argument is solid and there is equally solid datat to support them, then it's hard for me to argue against it.

[Viking Dan]

...we emphasize the need to train more aerobically rather than anaerobically. Why? because we want to maximize the use of fat and fat can't be used anaerobically... it needs oxygen to be 'burned'!

I thought the point was to add muscle mass to boost your metabolic rate? The amount of calories burnt in an hour of walking is probably comparable to the increase you'd get daily from putting on say 8 lbs. of muscle. I didn't imagine anyone was suggesting the calories burnt while actually lifting weights would make that big a difference.

While on the subject, how do you feel about CKD diets like BodyOpus or the Anabolic Diet (http://low-carb.org/faq/#Q2_2), where you do lowcarb all week while doing whole body workouts with weights, then switch to high carb on the weekend?

[Gabriel Guzman]

I thought the point was to add muscle mass to boost your metabolic rate?


True but it doesn't mean you need massive amounts of muscle. Small increases in muscle mass have significant improvements in your metabolic rate.


The amount of calories burnt in an hour of walking is probably comparable to the increase you'd get daily from putting on say 8 lbs. of muscle. I didn't imagine anyone was suggesting the calories burnt while actually lifting weights would make that big a difference.


If calories alone were the issue, that's fine but walking does nothing for muscle development in the long run. For me, at least, a better comparison is what kind of activity preserves more lean mass as opposed to which one 'burns' more calories.

While on the subject, how do you feel about CKD diets like BodyOpus or the Anabolic Diet (http://low-carb.org/faq/#Q2_2), where you do lowcarb all week while doing whole body workouts with weights, then switch to high carb on the weekend?[/QUOTE]

As stated in that link: "CKDs were originally designed for competitive bodybuilders". So, for somebody with those goals, not only that but many other specific ways of training and eating have been developed.

[Viking Dan]

If calories alone were the issue, that's fine but walking does nothing for muscle development in the long run. For me, at least, a better comparison is what kind of activity preserves more lean mass as opposed to which one 'burns' more calories.
OK. I'm not questioning that point. I thought you were implying you can't lose weight(fat) without aerobic exercise.

[Gabriel Guzman]

OK. I'm not questioning that point. I thought you were implying you can't lose weight(fat) without aerobic training.

We're talking in the context of exercise, right? Because you can lose weight without moving a finger :) .

My point was to differenciate between losing weight by doing something that preserves lean body mass (which in turns helps keep a higher metabolic rate, which in turn helps in the utilization of more fat) and something that doesn't necessarily accomplishes that.

[blueriversam]

Thanks, guys! I forwarded the blog and the Phinney article to my group. I also told them it was just FYI, for perusal and entertainment, and I was not arguing for or against any way of eating. Even though I am haha! I just do not want people to yell at me. I know that argument is the best way to convince, but I'm not into it.

Thanks again! Sorry I do not have time to post/read more often!

[Gaelen]

From the Protein Power Lifeplan FAQs from the old website:

Protein Power and Endurance Athletes--FAQs

How does this diet affect endurance athletes?
Quite well, once you've adapted to using fat as your main fuel for exercise. This process may take a week or two. Carbohydrate restriction causes a slight depletion of the glycogen stores. For a few days this condition may cause some slight fatigue and a feeling of being "out of gas." But it is the slightly glycogen-depleted state that encourages the body to turn to fat as the preferred metabolic fuel for muscle. And even in a lean person, there's a lot more fat than glycogen to draw from. In studies done at the naval air station in San Diego, Captain Charles Gray has shown that after adapting to the low-carb state, naval recruits not only equaled their previous endurance level, but also surpassed it. In many other countries that do well in athletic events, athletes tend to load up on fats more than they do on carbohydrates because all the recent studies show that "fat loading" promotes better athletic endurance.

Will the Protein Power Plan cause a decrease in endurance and athletic performance?
Absolutely not. In fact, studies have shown just the opposite-that people on a higher fat diet actually have much more endurance. This may sound wrong because it is so common for athletes to "carbo load" before a big endurance event. The whole idea of loading up on carbs is outdated nutritional advice. A problem that the U.S. athletes have had for a long time, because they carbo load before their event, is that when people switch from a high-carb diet to a higher-fat, low-carb diet, there is a decline in athletic performance at first. The reason is that enzymes have to adapt to the low-carb diet. But the decline is temporary, usually lasting three or four days-a week at most. Once athletes have adapted to the low-carbohydrate diet, studies uniformly show athletic endurance increases.

I am an athlete who "carbo loads" before my events. Why doesn't the Protein Power Plan support this concept?
When you're on a higher carbohydrate diet, the whole premise is that you're trying to stuff a lot of glycogen into your glycogen stores so you can run on it. But no matter how full you stuff them; they can get only so full, which lasts only a few hours. You can't run on glycogen for longer than that, so athletes "hit the wall." They run out of steam and they have to switch over to burning fat. If they started burning fat right at the beginning, they'd do much better. The other problem with carb loading is that becoming carbohydrate-adapted often means your insulin levels are increased. And in the face of elevated insulin levels, you can't access the fat stored in your fat cells. And the fat in your fat cells is you most important and most potent source of energy in any kind of endurance event. Remember, you get 9 calories of energy from 1 gram of fat versus 4 calories of energy from 1 gram of carbohydrate. No matter how well somebody's doing athletically, on a high-protein plan he or she could probably do better once allowed to adapt.

If I'm participating in a 3-5 hour athletic event, how should I plan to eat the day of the event?
If you have been following the Protein Power Plan, your body will utilize fat as its main energy source. You will basically be eating the same, with the addition of "snacks" during the event. Make these snacks small amounts of carbs combined with protein and healthy fats. An example would include bite size pieces of protein/carbohydrate bars, grapes, nuts, trail mix, etc. Glycogen stores tend to become depleted after about 90 minutes of continual exercise, depending on the intensity of the exercise. A small snack about every 30-40 minutes, after the initial 90 minutes of exercise, along with plenty of water and electrolytes will carry you throughout the event. Do not take in carbohydrates alone, whether in food or drink form. Carbs alone will increase your insulin levels and not allow fat to be released for energy metabolism. Skeletal muscle restores its glycogen levels at the highest rate during the first two hours after exercise, so be sure to replenish with low starch carbs, protein and healthy fats at this time.

I am a body builder, training for a competition. How do I incorporate a low carb diet into my routine?
A lower carb diet is the perfect plan for a body builder. It is very important to know what your lean mass weight is because your maintenance protein intake will be based on that amount times your activity level which will be somewhere around 1 to 1.2 grams or higher, of protein per pound of lean mass. Because your protein intake may get as high as 300-400 grams of protein per day, it is important to eat small amounts about every 1 -3 hours. Your carbohydrate intake will be well less than half of your protein intake, eating mainly the fibrous vegetables and a few fruits. Keep your fat intake to healthy choices and at a moderate level so as to force your body to burn stored fat as its energy source. This is what gives you that "cut, lean" appearance. Drink a couple of gallons of water a day and replace those electrolytes.