[crikli]

Researchers have not seen any evidence that the ketogenic diet (or any other diet that trains the body to engage lipolysis to a greater degree) increases exercise capacity.

They have seen evidence that these diets can retool the body to more readily use fat as an energy substrate. While this doesn't translate to performance gains, it can mean that on a multi-hour/multi-day effort that a self-supported athlete might need to have a bit less food in their packs as well as foods with a higher proportion of fat that are lighter. Lighter pack = faster athlete.

But...even low intensity exercise over long duration is going to result in the recruitment of FTa/FTb muscle fibers that run almost exclusively by glycolyis. So an athlete counting on fat to be the primary energy substrate has be really highly trained, practiced, and know their pacing thresholds really well to keep the recruitment of those muscle fibers to a minimum.

Best paper I know of on the subject is this one: https://static1.squarespace.com/static/55b7ffebe4b0568a75e33...

Best book I know of on long-duration effort is this one: https://www.amazon.com/Training-New-Alpinism-Climber-Athlete...

[GreaterFool]

I can only speak to my personal experience. I’m not an athlete but I lift, bike and so on. On empty stomach. I don’t eat before training. I could never do that on carb diet.

[evandev]

Speaking from my personal experience to counter this, I run in the mornings up to 1 hour on an empty stomach. While I don't follow one diet, a larger portion of my food is carb based.

I follow TFTNA (Training for the New Alpinism) and Uphill Athlete (Steve/Scott's new book) training regiments that Parent mentions.

They do talk about retooling your body to use fat reserves more than carbs. While I'm sure the evidence shows that keto diet might make this switch faster and easier, someone on a non-keto diet (carb based) can also do this.

[crikli]

Haven't read Uphill Athlete yet...I think it ships in a few days. Really looking forward to it and to going to see Scott/Steve speak in Denver.

[evandev]

I don't think I'll be able to make any of their talks because the nearest city is a bit away, but I do frequent their forums/site which has an incredible trove of information.

https://www.uphillathlete.com/

[crikli]

Agreed! I love that Scott is so active on there. Those guys are legit.

My other very favorite resource is Shawn Bearden's Science of Ultra podcast, which is where I learned of the research paper I linked in my first post. Here's the one on fat adaptation: https://www.scienceofultra.com/podcasts/19 . He has lots of pretty hardcore exercise scientists and researchers on. It's one of my favorite things to listen to while grinding up a hill. :)

[Buldak]

>I could never do that on carb diet.

Have you tried? I always run before eating (not as part of a regimen, it's just convenient), as I expect many do. And my diet is closer to inverse-keto than keto.

[GreaterFool]

It is fascinating to see that I have negative points by simply recounting a bland personal experience. Who did I offend this time? :)

[mikekchar]

My guess: It appears as though your reason for posting was to say "I could never do that on a carb based diet". However, you never established and reason for that conclusion. Each of us has our personal opinion on a variety of different subjects. We could all post that personal opinion without any corroborating evidence, but because there are a lot of people, this would create a comment section containing mostly noise. People would prefer to see comments based on research or personal experience that seems to strongly corroborate the conclusion. Generally it has been my experience that I do not get many down votes simply because people disagree or are unhappy with what I'm saying. It's usually because I am clearly wrong, or I have simply contributed to the noise.

I think that your comment falls into the noise category and is undesirable because of that. If you had explained personal experiences to show how you reached your conclusion, It think you would get a better reaction. If you also showed how other possibilities could be rules out, then I think people would find it very interesting and you would get many up votes.

[GreaterFool]

Downvoting on HN confuses me. I don't ever downvote anything, I think it's a bad idea. Upvoting is ok, downvoting should be removed.

Also, looking at comments, often I see only upvote and no downvote button. Why is that?

[detaro]

You can only downvote during the first 24 hours, and only comments that are not replies to you.

[newen]

I don't think that's true for most people. I do weight lifting in the mornings with only a coffee, dinner around 6pm the previous day with no snacks afterwards, and my diet is fairly carby.

[GreaterFool]

I found intermittent fasting hard on carb diet. It is super easy on keto diet. In fast I fast 2-3 days every now and then because it's just a seamless transition.

I'm not saying my personal experience should be considered universal, that'd be foolish. Just recounting that.

But it makes sense given how metabolizing fat and metabolizing sugar works. Insulin response, etc.

[newen]

Especially in the case of diets, I think personal experience should acccount for most of how you make your decisions. The human body is very flexible to different conditions, the science here is pretty flaky, that trying to make sense of diets by using logic only helps very little. Anyway I'm just repeating what you're saying, that personal experience may not be universal but it's important for yourself.

[sh4z]

I think it's more of a mindset thing and what you and your body is used to.