http://www.sciencedaily.com/release...51215094542.htm



Okay, so under conditions where runners would have burned mostly glucose for energy anyways, blocking lipolysis doesn't much affect fuel source. Sort of like taking a bottle of motor oil out of the trunk of your car, and seeing how that affects the fuel mix burned. It wasn't in the mix to start with. Even if fat manages to get out of fat cells and into muscle cells, high intracellular levels of glucose will still prevent much of it from being used for energy.

What any of this has to do with keto- or even just fat-adapted athletes is beyond me. When the default diet is high carb--and I think it still is for this group--the people who become competitive half-marathon runners will be the ones best able to adapt to a high carb metabolism in the first place.

For a few years, I volunteered at a local tri-athalon and got to see this up close. The front runners, male or female, had a marathoner's build: lean and long-muscled, a particular body type.

My husband was a gymnast in high school, but he would never be in this group. He's got a torso like a beer keg, a neck that won't fit in most collared shirts, and upper body strength like a caber-tosser... which is his genetic background.

The people who ran marathons well didn't become that greyhound shape because they ran marathons. Their heads were long and narrow, their feet were long and narrow, their shoulders were like half the width and breadth of my husband's shoulders.

There were some people with DH's build on the race... in the middle. They were fit, sure, but they were struggling the whole time.

Long distance endurance is not what they are built for. Kenyan marathoners... not to take away any of their heart or spirit, but they are built for it!

So...did they do a comparative study in keto- or fat-adapted athletes with a carbohydrate "blocker"?

Haven't Phinney and Volek done experiments on keto-adapted athletes?

Seems to me many of these studies are badly designed to bias towards carbohydrates. You find what you're looking for!

Yes, it appears they got the results they selected for with a 90-minute maximum run on a treadmill. This proves nothing. Performing an endurance event for 90 minutes wouldn't even require consumption of additional fuel during the event because usually there's enough glycogen stores for most of the duration. Agree with the previous comments that observe that these athletes were not fat adapted, so they'll favor glycogen over fat; they missed adding another group that were fat adapted and fat fueled with some method to measure fat-sourced energy (yet, the metabolism gets some glucose from fat due to the glycerol molecules in fat); and they should have had a control group to determine at what point fat was used (assume this is very difficult to measure).

Why bother? This is hardly revolutionary.

Exactly, but I'd love to see a fat adapted group that was restricted on carbs prior to the treadmill session just to see a real comparison even at that short of a duration.

My daughter is a triathlete and does low carb as she says she gets a longer, more reliable energy, instead of carbs which are in short bursts???? - her choice, after she and her co-triathletes did some anecdotal studies and trials. I didnt get involved, but I was surprised that she is taking low carb so seriously.

Jo xxx

Husband is a half-marathoner. And a good one. AND he's built like the racers that WereBear describes.

OTOH, the endurance athletes who do best on a keto adapted diet tend to be triathletes, or ultra marathon runners--people who go well past the legendary "wall" that glycogen users hit.

Also, running on a treadmill is NOTHING like running an actual race on a street. You can't reproduce the small variations in surface, the constant incline/decline of the terrain, even in places that are relatively flat, nor, as in most distance races, the gradual then increasing inclines to the top of whatever hill has been called "Heartbreak" for that particular race.

Not to mention the fact that most treadmills have a powered belt. This reduces the resistance and effort required to push the ground away exponentially (I like that word--not sure if it's quite accurate here, but never mind.)

It seems accurate to me, Barb. And is a perfectly good word, as well.

I am anti-treadmill biased, so much that when I was running halfs I would train on the track (27 laps to a mile!!!). Meanwhile, I would stare at this woman who was always there like me, and highly focused while running. We would talk shop in the locker room. I later found out why she trained on that treadmill every day. For the Olympic trials. While working full-time at a highly stressful job. And came in 19th. I ate my treadmill prejudice pretty quick.

We live in MN, and there isn't a decent indoor track at the club where Husband works out. So he runs on the treadmill for much of his training.

But as soon as he can get out to run, he does.

Treadmills for exercise are like grains for food: if that's what you have, use it. But there are better.

I've read that if you set the treadmill to an incline it helps offset the whole "your feet are propelled backward for you" effect.

We own a good treadmill that is NOT a clothes rack. DH uses it regularly to enhance his fitness level, and I say that's great!

I prefer weight training, alternated with walking outdoors. But I'm thinking of using the treadmill more often now that it's chilly outside. Yes, bumping up the incline definitely increases the work, and it's far better than...well, sitting here at my desk all day making conversation on this forum.

Hey, you could fix up a table for your laptop, and walk while you make conversation.