That’s not true at all.
Evidence?
Over consumption of Carbs, as in simple sugars is more of a problem than Fat (esp if healthy fats.) The really problem of course is the combination of refined carbs and fat, that is the main problem.
You made the initial claim, therefore you’ll need to provide proof.
The above statement is what’s called being intellectually dishonest.
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Not really you don’t become diabetic by eating fat.
So you agree.
I will have to say it depends. In my case (51yo long distance triathlete) it was a piece of the puzzle that made me faster.
If I were a coach, I will never prescribe keto as a performance helper without the athlete asking specifically for it and, even in that case, we would have to be talking races above the 5 hour mark or so.
In general I would say that caloric control together with smart carbs (periodification) are the way to go.
In a couple of years time, I hope some testing that currently is only available in physiology lab, became widely accessible with decent accuracy.
By then we will be able to know periodically where the athlete stands in terms of substrate utilisation and how the conditioning (nutrition and training interventions is moving the needle.
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I was watching GTN (GCN triathlon partner) a week or so ago about how to squeeze a proper swim workout into a very compressed time and, talking about the importance of the cool down, the presenter mentioned something like “it will also help to flush out the lactic acid”.
I hit the unsubscribe button immediately and did the same to GCN.
So, I really do not expect from them anything more than at best a kind of a mix between bro and real science.
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It surprises me that this isn’t really talked about. I have friends who get super into keto because they lose a fair bit of weight in the first couple of weeks, and swear up and down that they “balloon up” whenever they eat carbs for a day. I think doing keto successfully requires a good understanding of how the process actually works and the ability to be fairly realistic/objective about your results.
“messing up” your metabolism is largely a myth. Though it can be influenced by things like lean mass and activity levels, macronutrient composition or dietary history aren’t going to impact it to any significant extent unless you’re heavily restricting calories for an extended period of time- and even in cases of severe anorexia it bounces back within a couple of weeks of eating at maintenance.
Insuline resistance or underproduction definitely is metabolic damage. why would you put your body into constant survival mode?
???
Insulin resistance is the opposite of what happens on keto.
If you were a coach trying to make your athletes faster, you would never prescribe keto because it’s a sub optimal nutritional strategy for endurance athletes. If going keto actually made you faster, all the best athletes would be doing it. They don’t, because it doesn’t! The science is very clear. You would hope that people had a grasp of basic science, but some people still think the earth is flat, so maybe that’s asking too much. If you’re a fan of keto, by all means go for it, but people shouldn’t pretend that it’s the optimal diet for sporting performance.
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Yep! And the original Phinney paper outlining the benefits of Keto was flawed to say the least (an single outlier if I remember correctly, included in analysis that significantly skewed the data).
Even the more widely quoted studies are humble enough to say more studies are needed like the case of the one published about walkers by Louise Bruke.
My only point is that maybe there is a place for keto as an acute nutritional stimulus like I tried to do myself without any noticable impairment.
It would be great if I could have tested my fat burning ability at 70% of FTP before and after the intervention because it would be a decent measure of metabolic IM performance. Maybe the outcome was indeed close to nothing and I just got the gains from something else.
By the way I forget to mention another stress around going keto and discussing it openly.
For reasons I am yet to figure out, nutritional discussions (specially around carbs) tend to cause an abnormal level of aggressiveness that is indeed stressful.
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Keto involves long term, chronic restriction of carbs. Louise Burke definitely doesn’t advocate going down this path to enhance athletic performance. As far as “more studies being needed”, this is related to macro nutrient manipulation or CHO periodisation, not keto. There’s an important difference. Dietry interventions can definitely influence what your body uses as a fuel source. Studies suggest these adaptions are short lived. You can also force adaptions through training stimulus, whilst consuming carbs and training at higher power outputs.
I’ve never witnessed aggressiveness towards people that are keto, more frustration/confusion at people pushing pseudoscience. As I’ve already mentioned, if you like keto, great! Just don’t try and sell it for something that it’s not.
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Impeccable timing
New podcast out with Louise Burke "Ketogenic diets for cycling performance: the future of elite endurance sports?"
Worth a listen. Spoiler: She doesn’t recommend going keto 
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As I said before, I tried it myself and I cannot say if it was a critical positive factor but I did lost weight and I would add my scale (which measures fat percentage) shown no lean mass loss (scales are very faulty but that was the only measurement method I had available).
The only segments of the power curve where things were heading south were for efforts below one minute.
I am not even sure if I was in ketosis. The experience took me around 6 weeks and I just tried to be below the 100g mark in daily carbs ingestion.
One aspect that deserves attention in general is the context of the publish evidences.
I am 53. When I was 21, I could eat tons of simple sugars without putting on any weight even if I was not doing a lot of sports. Now I lift the gate a bit and I immediately see my body fat increasing a couple of kgs in less than a month.
The vast majority of the science out there is focusing in 19 to 26 males.
Can I just assume my 53 years old body will react the same to the same stimula when my metabolism is now very far from what it was when I was the same age of the subjects.
Science is all about curiosity, questioning, doubting, trying new contexts.
Bro science and pseudo science is everywhere but there is also a sort of an attitude that extrapolates specific study results much beyond their context, very often in a very dogmatic and aggressive way that in my opinion is contradictory with the notion of science itself.
Having said that, my position is that I gave keto a chance as a very acute and time limited intervention and in my very specific case I did not find a loss of performance around the effort levels that I race. The weight loss made my running faster for sure.
This is consistent with the chart you shown since my race power is around 70 to 80% of FTP which would translate to something below 65% of VO2Max.
Would I do it again? Maybe if I plateau too soon in terms of weight loss during an A race prep.
Will I advise anyone to do it? Probably not due to the stress factor involved and stronger evidence pointing to the other direction.
One final word. I did not listened to this specific podcast but I remember a previous one with her. When asked about the criticism the keto/LCHF field made about the intervention being so short and keto should be viewed as a long term thing she said that they found that some very relevant markers were already showing a relevant adaptation only a week or so after the beginning of the keto diet.
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Great threads people, thanks for the responses. Best takeaway I get from this is that Louise Burke is on a podcast! Didn’t know that and will now follow! She’s been around a long time and worth listening to.
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As you’ve proved.
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That is precisely the kind of aggressiveness I was talking about. Thank you for proving my point also.
Just read the discussion on this paper, namely when it refers to previous studies, and tell me that there I no room for some reasonable doubt about LCHF as a tool for an amateur very long distance athlete.
Yes… it is Louise Bruke paper.
My IM power is around 190w (0.7 IF) and in a flat course that would translate to 5 hours-ish.
So it is something like 3500kj (same as kcal). If I can use 1g of fat per minute at that power, it is 9kcal per minute or 560 per hour which means 2800 for the bike leg. So my deficit in the end is just 700kcal I need to top of with carbs.
Unfortunately I have no time to train to a point that would give me that adaptation just from working out.
Again. I do not reccomend keto. But I cannot buy the idea that there is no place for that strategy acutely in very specific cases.
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