bbbean 

It is entirely conceivable to me (based on purely personal experience and anecdotal evidence) that "fat adapted" is likely just a matter of what your body is used to in the same sense that if your training is primarily 5 minute intervals for 1 hour that you're going to get very good at doing 5 minute intervals for an hour. Sports nutrition is still as much an art as it is a science, given the number of contradictory studies, low ns, lack of good controls, and the number of people with a financial interest in any given outcome.

Seattle Forrest

Competitive XC skiers are the fittest people on earth, as measured by VO2max. They get that way by training and competing at extreme intensities. This isn't compatible with keto. You can't go/stay beyond your anaerobic threshold without carbs. People at the highest levels of endurance sports don't do keto because they want to compete at a high level. It's fine for going slow.

Outside of competition, intensity is still important for cardiovascular health. And people who enjoy the longest lives and the longest periods of good health over the course of their lives take a large portion of their diet from carbohydrates.

wolfchild

Ketosis and fat adaptation is strictly a "survival mechanism", which allows humans to survive during food shortages...Ketosis and fat adaptation was never meant to be used as a " healthy lifestyle choice", especially for people who are physically active, train, workout, compete in sporting events or are trying to achieve long term fat loss.

aclinjury

no doubt xc skiers are fit, but keep in mind that testing protocol matters in vo2max testing. XC skiing involves more muscle recruitment (ie, upper and lower body) than cycling and running, so xc skiing test is almost always going to show a higher vo2max.

Seattle Forrest

@aclinjury Given that, do you think a cyclist or runner (so only trains in their sport) would be able to pump as much oxygen if you put them in a specialized erg bike or treadmill that somehow used as much muscle, without requiring skills they don't have? Not a gotcha question.

PS I hope your injury has healed by now.

redlude97

https://www.sciencedirect.com/scienc...26049515003340

Carbonfiberboy 

Ketogenic fat adaptation is obviously a real thing if you stick to it long enough. However, from your linked article:One does not have to read between the lines to see that this is another nutrition study looking for facts to support the authors beliefs.For a little balance, one might also want to look at Key Takeaways from International Society of Sports Nutrition Position Stand on Ultrarunning Nutrition

From that position paper: And etc. One might also point out that ultra running is not like what most of us call running.https://www.womensrunning.com/2016/0...marathon_59491

and is absolutely not comparable to bike riding in hilly terrain: on my group ride this past Sunday, 58' in zone 4. And I'm just an old, though trained, duffer. I know zero riders who eat LC.

Seattle Forrest

I know ultrarunners, they're all badasses. You have to be, to run 50 miles at a time. Don't let the pace fool you, you're slower on dirt than on pavement with the same effort, just like on a bike. And around here they do insanely hilly runs.

aclinjury

Good question! Well I'm no physiologist, but I'll venture a guess, and anyone can correct me if i'm off base.
Elite marathoners, just like elite endurance anything, have a huge central cardio system, i.e, the heart. This is the fuel pump. Then, you also have the muscles, and these constitute the "engine" that consumes the fuel. Then, you have the lungs for oxygen, these are the "air intakes". You will need all 3 components to work optimally together for a fast running car. The runner and the cyclist, in this scenario, lack "engine utilization", i.,e they have huge fuel pump (heart), huge air intakes (lungs)... but their engines (muscles) are small because they not using all body muscles like an xc skier or rower could. So, if somehow, we could put the runners or cyclists on a contraption that will allow them to ulitilize more of their upperbody muscles (eg, arms and shoulders), then they will mostly also exhibit a higher vo2max.

Having said that, at the most elistist levels of cycling, these cyclists' vo2max's are very close to that of elite xc skiers too. But at the average and club levels, of athletes in xc skiing (and rowing) will surely show higher average vo2max.

Now here's a corollary in cycling. Lighter riders, because of lesser muscle mass (smaller engine), tend to have a relatively under utilized fuel pump, ie., their heart is begging their muscles to work harder so the heart can have an opportunity to max out. So for lighter riders, it's best that they attack at every opportunity on a climb for utmost utilizaiton of their heart's capacity, and thus putting the bigger (and steadier) climbers into the redzone should the bigs try to follow. Guys like Froome and Wiggins do not like to climb in burst, they prefer the steady tempo, and that's why Contador has said that Froome without Sky is not the same contender (because if Froom is forced to cover, instead of having Sky pace him).

I have done both cycling and running, and to me, running has and will always be the toughest endurance sports compared to cycling, skiing, rowing, swimming. The reason is obvious, running impart tremendous impact and demand much more muscle and joint supports that do not reflect in these various physiological tests.

aclinjury

that's right. In easy time, one should try to eat less caloric dense food (because we're not walking for days trying hunt).

redlude97

I'll start off by saying I've never tried or ever will try a Keto diet because I'm in agreement that it doesn't have application to the type of riding most of us do that involves suprathreshold efforts that require glycogen even for LC athletes, but the question was if any adaptions even occur which the study clearly shows


Whether or not you define that as a difference in performance depends on the objectives of the athlete and their specific exercise intensities and nutritional requirements during the activity and whether that has been utilized at an elite level in any of those types of activities

aclinjury

artickle:

Kenya’s Elite Runners: a study on the diet of African Champions

And at the bottom, there's also a mention about the Tarahumara Indians, who are known for ultramarathons prowess, and their diet (which is predominantly carb based).

Food for thought.

aclinjury

well for kicks, I looked up some "ultra endurace events", like the Appalachian Trail run (which takes 40-50 days).
So here are some past but recent record holders mentioned in below articles:
https://www.runnersworld.com/news/a2...-speed-record/
https://www.nytimes.com/2016/09/19/s...il-record.html

So I looked up their diets, and none are keto. They're all huge carb eaters. I believe at least one of them is even a vegan.

redlude97

Jeff browning and zach bitter are two notable elite keto runners. Your question was if any elite athletes utilized it.

Carbonfiberboy 

Not an ultrarunner, but on the bike the big caloric issue is moving the calories across the stomach wall at high intensities, like on a long climb. The best is a mix of maltodextrin and fructose, the worst is fat. I know some ultrarunners eat bacon during their events. I read an interesting story of a keto PBP rider who got way behind on his calories, had to stop at eat ~1500 calories of carbs to keep going and then kept the carbs coming. A good and very frequently used strategy by keto runners is to be adapted but then on the run to eat mostly carbs. The only downside of that is that they're not carb-adapted and thus can't produce as much power on carbs as the carb-adapted. OTOH they burn more fat and thus need to eat less carbs to keep up their energy balance. However because of the high energy demands of competitive cycling, there are no keto GT riders.

aclinjury

honestly I don't follow the "ultra" scene, and while I don't like to discount people's achievement, but for any sporting event to be "elite", it must has breadth of competition. I don't know who zach bitter is, so I googled him up. It looks like one of his fame is breaking the 100mile "world record" run. So I googled up the 100mile competition events. So here they are:

1. World record established by a Russian guy named Oleg Kharitonov here

2. Zach Bitter 100mile run in 2015 attempt at American record

3. a 2014 Desert Solstice event

Judging from the breadth of competition, I would not call these 100mi events "elite" events. They are filled with age groupers and "finishers". Again nothing wrong with personal achievements... but Olympics and the major big name marathons are where the elites come out to play.

aclinjury

The graph above doesn't tell the whole story though. When a person does high-fat diet, his body will adapt to a higher content of fat intake by up-regulating the fat-metabolism machinery, so he becomes more efficient at metabolizing fat, as expected. At the same time, his body will down-regulate the machinery for carbohydrate metabolism, so now he's less efficient at utilizing carbs. What the above graph doesn't tell is that in order to metabolize fat at a higher rate, the person will also need to... consume more oxygen to do so. The any benefit of higher metabolism is offset by the need to greater oxygen consumption (1). So in the end, his vo2max may be lower than had he been on a highcard diet, and vo2max is still (although not the sole one) an important factor in performance at intensity.

So in an event where the athlete will at times need to go beyond 95% vo2max effort, the low fat athlete will basically has zero room to respond. Now if the event is one where the athlete goes at pretty much at steady, then it's ok. I ask though, how many of us in here cycle at a steady state? Every guy I know want to hammer at some point in the ride, it's part of the weekend fun.


(1) https://examine.com/nutrition/low-ca...for-endurance/

aclinjury

pretty much. Keto folks always like to bring in the "ultra" events, but even here, there are plenty of high carbers. So why bother with keto?

redlude97

Sorry not interested in an argument with moving goalposts. At least you are willing to admit that adaptions do occur, but there is alot wrong with your understanding of the physiology that is going on here

Seattle Forrest

For what it's worth, Heather "Anish" Anderson was a vegan when she set the unsupported FKT (fastest known time) on the Pacific Crest Trail. I don't remember the exact numbers, but she basically walked 50 miles a day with 5k elevation gain and loss every day for two months. I think she's the only person ever to FKT the Triple Crown.

aclinjury

admit? I'm not admitting anything other than what the science say. If something is wrong with my understanding (which I referenced), then state it. If you're not interested in debate, then neither am I. Ok that's fine. But I'm still waiting for the keto world to light up the Olympics and marathons though.

aclinjury

hmm yeah,, those guys are impressive, I couldn't do that.

But honeslty I don't really follow the "ultra endurace" scenes, and the only reason why I look it up is because in almost every discussion about diet, nutrition, and athletic performance,.. there is ALWAYS someone(s) from the keto world chiming in about how being fat-adapted (whatever that means) and ketosis would do very well in ultra endurance events,.. it's as if their claim to athletic legitimacy is ultra endurance.. and in the process they muddle the parameters of "athletic performance", talk about moving the athletic performance goal post. But ok, when I look up the ultra scenes, I find that in fact most of the fastest people there are in fact either on a high carb diet, some mix diet, or completely vegans,.. and those who are on the keto diet.. would need a relatively huge injection of carbohydrates during their competitive run. Yeah, keto this, keto that,.. then carbs for competitive runs. So why even bother with keto when vegans and non-keto people have run the Appalachian Trail and others similar feats at impressive times equating or surpassing most guys on keto diet? Why bother with keto and lose the high intensity performance part of life? not to mention following a very restrictive diet?

The bottomline is very simple, humans have evolved with 2 very sophisticated ways of metabolizing fuels (ie, fat and carbohydrate metabolism pathways), if you take away any of those fuel sources, then performance is bound to be affected. This is all over the literature: no carbs, no performance. No human population has been shown to be in ketosis, not the Eskimos, not the Maasai, no one. But apparently in the Western Hemisphere, there is an enclave of ketosis from mostly rich well-to-do white'ish middle-ish class? (with research sponsored by the meat and dairy associations). For the rest of the world, carbohydrates are still the preferred choice of food (for many reasons, one of which is economic).

I personally don't like to use the ultra events in my discussions of athletic performance though. Reason is when using such events, I would have to look at the breadth of competition, and to be honest, competitions in these events are almost nonexisting, and anyone, you and I, all know that when competition is lacking, then so is the quality of performance we see from it. It sounds like i'm diminishing the achievements of participants in these events, which I'm not. Don't like to be accused of moving the athletic performance goal post!

redlude97

Go back and read the article you linked more carefully and see if it matches up with your summary, or better yet read the actual article its referencing https://physoc.onlinelibrary.wiley.c....1113/JP273230

OBoile

As someone who participated in a fringe sport for several years, you have a good point. To further that, when the talent pool isn't particularly large, it becomes possible for more types of people to win. You can win by being a truly elite talent with mediocre training and nutrition, or by being a decent talent who has the other stuff dialed in pretty well. Contrast that with mainstream sports, where you pretty much have to have both elite talent and good training/nutrition to be the best. As such, it's always a good idea to follow what the top athletes are doing, but to take it with a grain of salt as it isn't necessarily optimal.

fly135

What if you don't have any spare fat to burn? High carb, high fiber works for me.