Ketogenic diets and exercise performance

[Illuminate]

Far from being brilliantly written but an interesting read nonetheless. Food for thought.

Cheers,
I

Amendment: Linky: http://www.vespapower.com/the-emerging- ... daptation/

[ITTY]

Did you intend to link to an article?

[Illuminate]

My apologies. Linky: http://www.vespapower.com/the-emerging- ... daptation/

Cheers, I

[jpanspac]

Any paper that claims that "a seismic shift is coming and a complete rethinking of how to perform will emerge" based on just one study is suspect.

[boots2000]

vespa=snake oil?

[KWalker]

Keto diets for endurance performance are absolutely stupid except for (maybe) ultra endurance types. Even then the best ultra runners eat super high carb diets. Anthony Colpo has a great two piece article on the subject and Inigo Mujika had one as well.

One thing people forget is that ketones and fat take more calories to produce the same amount of ATP and produce it at a slower rate. Not an efficient fuel.

[Illuminate]

A much better article from none other than the doc himself.

http://www.53x12.com/do/show?page=article&id=132

Interesting that the theoretical max energy yield of fat burn is 1000kcal/hr (equating to roughly 300whr)

Might be a consideration for a few upcoming longer Audax events.

Cheers, I

[AGW]

There are a lot of overweight, sedentary people who have seen positive changes to their health with this type of diet. They thus rave about it on the internet and spin it off into a whole paleo/primal/atkins/carbs-are-bad ethos. Bodybuilders have been using keto diets for decades, and now it's time for all the other athletic niches to try it out.

From personal experience, it's a difficult and unsatisfying diet in all its variations. They're logistically hard, I never experienced the promised rush of energy once you get over the hump and into ketosis, and my performance tanked. Forget about anaerobic efforts.

If you're fat and zone 2 is all you aspire toward, maybe this is the diet for you.

[boots2000]

THIS!
When you drill down into a success story about a low carb diet the success is usually from the weight loss and the fact that the individual started to train much more- not the substrate of the diet.
If you start training and lose 60 pounds you could draw the conclusion that whatever diet you were following was successful.

There are a lot of overweight, sedentary people who have seen positive changes to their health with this type of diet. They thus rave about it on the internet and spin it off into a whole paleo/primal/atkins/carbs-are-bad ethos. Bodybuilders have been using keto diets for decades, and now it's time for all the other athletic niches to try it out.

From personal experience, it's a difficult and unsatisfying diet in all its variations. They're logistically hard, I never experienced the promised rush of energy once you get over the hump and into ketosis, and my performance tanked. Forget about anaerobic efforts.

If you're fat and zone 2 is all you aspire toward, maybe this is the diet for you.

[AGW]

Yeah, I think it's similar to when someone has a particular aspect of their bike fit that goes severely against the tide but they claim it has given them huge boosts in power or comfort or whatever. Like drilling cleat holes in the heels of their shoes. Oftentimes it's because their fit was so screwed up beforehand that anything represents an improvement, at least for a while. But to continue to grow as an athlete... or to even train on the steep end of the power curve, forget it.

[Tapeworm]

Similar to above - all my readings for keto diets is that it is a waste of time for anything other than extreme (12hrs+) *very* steady state exercise.

The studies thus far show that any effort range beyond "plodding along" suffers on a low carb/high fat diet (different to keto I know).

Best quote I saw: "Carbs - so unnecessary that the body goes through a complex metabolic process to create a poor facsimile."

As AGW points out the extreme of diets and their purported benefits is usually tied up in a whole bunch of confounding issues.

Common sense, science and moderation have no place with most of these diet extremes.

[AGW]

I think it's been discussed tangentially on Wattage over the years as well. In the face of the obvious drawbacks, there was a defender who pointed out that paleo doesn't necessarily have to be a "low carb" diet, and one could simply get all their CHO from tubers and fruit. KWalker dressed him down with math; 1 sweet potato or 1 gel

[boots2000]

I actually track my grams of carbs to make sure that I get enough carbs on heavy days- this helps me to train at a better level and recover more quickly.
I am closer to the 60% of diet in carbs.
I am actually 2-3 lb. lighter than same time last year and I am not a big guy.

[KWalker]

A diet of 60% + CHO allows one to store an extra 600+ cal of glycogen. Considering that a 1hr FTP effort could burn 1000kj, this buys you a hell of a lot more gas.

The problem is that one can't just eat a bunch of carbs for a day and get this effect. Their body would retain a bunch of water and since it hadn't been storing much CHO or able to process it they'd be fairly CHO inefficient. Louise Burke has discussed and studied the shortcomings of training low/keto and racing high/replenished.

I, like Boots, have found that CHO is something I really have to focus to get enough of. On a day with a 4-5hr ride I found I was almost never getting enough for the volume to be sustainable.

[boots2000]

This is true even for riders who are small.
I am weighing 63ish kg these days.
A big training day (healthy ride and gym) can put my carb needs in the 800+ gram range.
That is a lot of carbs!

A diet of 60% + CHO allows one to store an extra 600+ cal of glycogen. Considering that a 1hr FTP effort could burn 1000kj, this buys you a hell of a lot more gas.

The problem is that one can't just eat a bunch of carbs for a day and get this effect. Their body would retain a bunch of water and since it hadn't been storing much CHO or able to process it they'd be fairly CHO inefficient. Louise Burke has discussed and studied the shortcomings of training low/keto and racing high/replenished.

I, like Boots, have found that CHO is something I really have to focus to get enough of. On a day with a 4-5hr ride I found I was almost never getting enough for the volume to be sustainable.