Try doing a 100km bike ride on an up/down road circuit, with fat as the main fuel.
EDIT: lol, downvotes. This is not about your metabolism while you're sitting on a chair at work, typing on a keyboard. This is about extreme endurance. I suggest you actually go ahead and try it, before thinking you've formed any sort of informed opinion on the subject.
Your body definitely needs time to adapt to a fat based diet, but it can satisfy all your energy needs.
I've also done centuries with sugary 'energy' foods. I frequently found myself having to pull over or dangerously balance in order to keep my blood sugar high by dosing myself every 45 minutes. Your stomach churns, your teeth feel awful, being constantly in service to your legs. Burning the fat is a much more comfortable proposition.
Here is a link to a summary, I couldn't find the actual research articles I was thinking of though.
http://www.pponline.co.uk/encyc/sports-nutrition-should-athl...
It is fair to point out (which the article does as well) that the athletes were running at 75% of V02 max, which is lower than when racing in cycling. I ride a lot, and anecdotally I had a cycling teammate that changed his diet to consist of primarily fats for 6 weeks. The first few weeks his body was adjusting and his endurance and power dropped dramatically as you would expect. After 4 weeks, though, he had come back and had a really strong season.
The way I understand it is that as intensity increases it becomes more difficult for the body to convert fat for a large source of fuel, and glycogen becomes the largest contributor to energy. I know the feeling of a "bonk", when glycogen depletes, is a really strange one and all fuel is coming from fat at that point and intensity has to drop by quite a bit in order to continue.
Our bodies are pretty amazing
There's only one thing that gets you out of it quickly - and that's a shovel full of carbs.
Also, doing a 100km bike ride with fat as the main fuel would actually be exceptionally easy if you used the proper technique, because the entire purpose of the gearing system on racing bikes is to ensure your exertion remains the same. It would just require training with this goal in mind, like Timothy Oslon who's a successful ultramarathon runner.
> I suggest you actually go ahead and try it, before thinking you've formed any sort of informed opinion on the subject.
I would suggest you do the same, because you don't seem too well informed either.
I am not an extreme endurance athlete, but I have heard multiple anecdotes of extreme endurance athletes eating cheese pizza slices during their 100-200 mile runs. It's actually a fairly common theme ...
ALSO: Do NOT meta-discuss your own downvotes. Don't interrupt the discussion to talk about the scoring.
Well cheese is a good mix of protein and fat, and the base is full of carbs
Nah, let's do exactly that. I see too many controversial posts which are otherwise good quality and contribute to the discussion, get downvoted because people don't agree with them. I don't care what pg says - downvoting merely for disagreement is fucking stupid, and it's lazy.
If I wanted a hivemind I'd go to proggit. When this community votes on posts based on quality, and not on who wrote it and whether they agree, then we can call people out for complaining about downvotes. Until then (i.e. until never, probably), if you feel you're being unfairly downvoted, bitch about it as loudly as you want - you will get at least one upvote from me when you do.