|
Nov 2016
12:11pm, 16 Nov 2016
12,483 posts
|
Dvorak
I have a theory that anyone trained up to run a marathon should be able to do it without taking on extra fuel. However, they way they would do it would be by running slowly. Using ballpark figures of needing 3000 kcal and storing 2000 kcal, if you ran at training pace you might have a 50/50 carbs/fat split. Maybe even higher on the fat. It's just that that is not how the vast majority (quite understandably) approach their marathon races.
But, I think there is more to it than that. I've read about studies demonstrating that even swilling a sugary drink around in the mouth during exercise can have a similar effect to ingesting carbs during exercise. And I've seen people running low in hms (even to the point of collapse) and 10Ks who have been perked up by a gel or a sweet; and total carb depletion seems a bit unlikely in those cases.
This then leads me to think that the body can be acting as if it is severely carb depleted long before such depletion actually happens (and can be fairly easily fooled into stopping acting this way). This would make evolutionary sense perhaps as it would be more adaptive to have a mechanism to throttle back and save some carbs for when they are really needed rather than just use them all up and have to rely on fat burning/ketosis. But through training and/or or taking an approach like tipsku's one can marshall one's carb resources considerably better.
That's also lead me to think that those "paleo fat burning machines" may have the wrong end of the stick, especially if their true energy usage figures are low like Gobi's. Instead of laughing at carbs and running off fat, they are actually getting maximal benefit from their limited carb stores.
|
|
Nov 2016
12:41pm, 16 Nov 2016
31 posts
|
bakedbeano
I think i've read the same articles Possibly there is a release of insulin mediated by the taste buds recognising sugar, I seem to remember that there was no similar reaction from swilling with artificially sweetened drinks.
|
|
Nov 2016
1:09pm, 16 Nov 2016
16,700 posts
|
flanker
I suspect there's some truth in that; all associated with he Central Governor theory and the brain being over-protective of the body.
I think it also depends on body type. I very much doubt there is a linear ratio between body weight and glycogen storage (think differences between weight as fat or weight as muscle) whereas the ratio between fuel needed and weight is (roughly) linear.
|
|
Nov 2016
2:06pm, 16 Nov 2016
59,292 posts
|
Gobi
I have run a 3.15 marathon on nothing.
All about control.
Only noticeable things afterwards
I was thirsty
|
|
Nov 2016
2:08pm, 17 Nov 2016
218 posts
|
dibbers
Gobi
was that marathon done at a consistent pace, or did you slow down in last few miles?
|
|
Nov 2016
2:19pm, 17 Nov 2016
59,308 posts
|
Gobi
I got a little quicker - understand I had a 2.40 pb and this was a steady training run.
I ran a 33 min 10km the next day
|
|
Nov 2016
2:25pm, 17 Nov 2016
219 posts
|
dibbers
ah, that's why you didn't need any fuel
|
|
Nov 2016
2:30pm, 17 Nov 2016
59,314 posts
|
Gobi
Was still an interesting experiment.
I ran 2.4x on 4 gels
|
|
Nov 2016
2:41pm, 17 Nov 2016
220 posts
|
dibbers
My problem is that I always feel nausious after around 17 miles and can't ingest anything
|
|
Nov 2016
2:44pm, 17 Nov 2016
1,295 posts
|
larkim
We all "know" that a fast run is more draining than a slow run. But does it use a different amount of calories?
Taking Gobi's example, he's moved a XXkg body from point A to point B 26.2 miles away. He's taken longer to do it, so as work = power x time, presumably power has reduced and time has increased. Is the amount of work the same? Or the calorific burn?
|
Daniels Running Formula. The Definitive Wire.
Jul 2023