Marathons and Weight Loss

heybales

hermann341 wrote: »

glevinso wrote: »

hermann341 wrote: »

My opinion is weight loss and running marathons are not mutually exclusive. I was 235ish in Dec 2013 for my second marathon (4:56) and about 210 in May 2014 for my third (4:28). I'll be about 180 for my fifth in 2 weeks (Monumental) and expect to finish around 3:45. Also, my diet was less than 20% carbs.

While not mutually exclusive you *do* have to be careful to still fuel your body for the training. You can under-fuel a *little* to drop weight but it is dangerous to try to drop significant weight, at least towards the end of the build.

As a low carber, my fat is my fuel. I save my glycogen for my brain. I'm about at my desired weight, so I will be transitioning to maintenance, but my carbs will stay at about 20%.

Low carb'ing may improve the ratio's of energy source for fuel during training - but you are not defying the metabolic pathways when your intensity increases and carbs are indeed used more and more.

Best I've seen from someone actually measuring their own results in keto compared to out - already fit so no change there, was at prior level of 50% fat/carbs was changed to 55% fat in keto. Still 45% carb usage at that point. And lactate threshold lowered for high end efforts when it was total carb burn - but that didn't matter to him because he was doing endurance anyway, not sprints.

Besides, the muscle stored glycogen can't be put in to the blood stream for the brain to use anyway, so perhaps you are thinking about and talking about the liver stores being maximized, but then again, when in keto you aren't using carbs for the brain, and 20% carbs isn't getting you in to keto anyway.

I think you are just making sure you stay in the Active Recovery (aka fat-burning) HR zone to maximize fat usage, which is great for ultra-endurance. Rather a slowdown otherwise for most.

hermann341

heybales wrote: »

I think you are just making sure you stay in the Active Recovery (aka fat-burning) HR zone to maximize fat usage, which is great for ultra-endurance. Rather a slowdown otherwise for most.

So what would that be for someone age 50? I just did a 22 mile, 3+ hour run on nothing but electrolytes and water, with an average HR of 145.

glevinso

heybales wrote: »

I think you are just making sure you stay in the Active Recovery (aka fat-burning) HR zone to maximize fat usage, which is great for ultra-endurance. Rather a slowdown otherwise for most.

Pretty much all that would be able to accomplish in a low-carb situation is Zone1 type stuff. Slow for a "marathon" but I guess it works at ultra-type distances. But even then you want something that you can actually metabolize for fuel, which is going to be carbs. Fat has to convert via enzymes into sugars so that you can burn them and that process takes longer than the available time needed to use them. This is pretty much the definition of "the wall" for marathoners. You run out of free blood glucose and glycogen, and the best you can really do then is move slowly under "fat power"

heybales

hermann341 wrote: »

heybales wrote: »

I think you are just making sure you stay in the Active Recovery (aka fat-burning) HR zone to maximize fat usage, which is great for ultra-endurance. Rather a slowdown otherwise for most.

So what would that be for someone age 50? I just did a 22 mile, 3+ hour run on nothing but electrolytes and water, with an average HR of 145.

That would be the top of my Recovery HR zone right now (based on Lactate Threshold), and my HRmax hasn't lowered in the last 10 years, so I'd expect it to be the same.

My first 2 marathons were accomplished with no mid-race fueling for blood sugars either, and done at average 8:30/mile pace.

So ya, entirely possible. I also specifically trained that way for them - Maffetone method, maximize aerobic function, or fat burning, while going faster. Worked great with the Zone diet at the time.

It's a misnomer that the mid-race fueling is for your muscles - you could never take in enough fuel to be absorbed during the run to actually fuel the muscles and that high rate of calorie burn. Best you can do is keep blood sugar and brain function where it's at.

The training you've done has maximized both fat usage and carb storage in muscles - so you got enough to last - which is what is required.

As mentioned above, the real wall, running out of muscle glycogen stores, and now only fat and blood sugar as fuel source can be used - causes a huge slowdown to accomplish, as there just isn't that much blood sugar available for much intensity.

hermann341

Well, I haven't hit my top speed yet, and expect to qualify for Boston with my March marathon. So whatever I'm doing seems to be working.

GiddyupTim

I see plenty of heavy people running marathons who finish better than I ever could.