[wartijn_]

> This is completely false

No it isn't. The comment to stop eating carbs was aimed at someone who is trying to do a half marathon in less that 2 hours. Like you say yourself this is way to short to deplete your carbs, so to just stop eating carbs seems like exactly the "bad advice that needs a lot of heavy caveats" that the parent poster was talking about.

[haspok]

There are other reasons for going keto even for a half-marathon - and who knows, maybe the full distance is next.

You don't have to worry about timing your meals, or "carb-loading" which is misunderstood and yet done by so many beginners just because they read about it and they disrupt / overload their digestive system, and causes more problems than has benefits (if any - guess how I know that).

I cannot really explain the feeling of not feeling exhausted after a few hours of "exercise" to someone who has not experienced it. Yes, your muscles are sore, yes you are thirsty (an unwanted side-effect of keto - you need to manage hydration!), yet your head is clear, your mind is fresh and you are ready to pounce. You feel like Duracell Bunny.

Is your experience different? I'd be happy to hear about it - maybe it doesn't work so well for everyone?

[scott_w]

You can't even explain your position to me and I ran 23km on Saturday without feeling depleted at all. I regularly bike over 100km without being depleted. I race middle distance triathlons and the only time I run out of energy is when I stop eating carbs.

You're talking absolute nonsense.

[rojeee]

I think OP is referring to people with poor metabolic flexibility. If not fat adapted, then you have enough glycogen for roughly 1600 calories worth of running at which point you bonk and can’t continue. If you are metabolically flexible then you substantially reduce the amount of glycogen you use at the same effort as someone who is not fat adapted. If you are very fat adapted then you can basically continue indefinitely at sub aerobic threshold pace as long as your muscles are strong enough to support you. I also have a low carb diet. It works very well for me. I was metabolically tested and burn roughly 2g of fat per minute at aerobic threshold which is pretty insane. It gets lower as you increase pace as body switches over to glycogen and then anaerobic respiration. People on high carb diets won’t get anywhere near close to that. My Aerobic threshold is >85% of VO2max (anaerobic 95%) and I can keep that up for hours even when apparently glycogen depleted (as restricted carbs in the preceding days). My running has improved immensely since going low carb - run faster with less effort and recover much faster.

Obvs if I’m racing then I use carbs.

[scott_w]

I think that’s different. There are people who can do what you say, eating less carbs, but mostly they’ve been doing that their entire lives. It’s not something you can build a training and fuelling strategy from.

Dylan Johnson does a great dive into fasted training on YouTube, which I’d highly recommend.

[rojeee]

Thanks for the recommendation - will have a listen today.

[rojeee]

I might add that if I’m racing or doing high intensity work, then clearly I take carbs like everyone else.