Dr. Stephen Phinney: Does ketosis enhance athletic performance?

Dr. Stephen Phinney: Does ketosis enhance athletic performance?

July 25, 2019 4 By William Morgan


I think this is something
near and dear to our hearts.
– Yeah, wow.
Do we have an hour to–
– Yeah, I think we could
spend a lot of time on this.
Our collaborator, Jeff Volek,
that is at Ohio State, and
also a co-founder of Virta,
he actually has been looking
at this a lot lately in his research.
Back at Yukon, a few years ago,
he brought in 10 high carb athletes,
and 10 keto adapted low carb athletes–
– These were elite, ultra runners.
– Yeah, elite, ultra runners,
that do ultra marathons,
or some of them were triathletes.
So it was elite, ultra endurance athletes.
And 10 of them were keto adapted,
and 10 of them were on a high carb diet.
He brought them in to run for three hours.
And looked at all of their performance
during that time, and
then during recovery.
Probably not surprisingly, the low carb,
keto adapted athletes had higher
peak rates of fat oxidation,
and a higher mean rate of fat oxidation
throughout their run.
But the really interesting thing is that,
when it comes to athletic performance,
people seem to be concerned
about muscle glycogen.
And they’re worried that
if your low carbohydrate,
and keto adapted that you’re maybe gonna
run out of muscle glycogen.
Feel like you hit the wall
and not be able to perform.
So they did muscle biopsies in this study.
And what they found was
that the keto adapted,
low carb athletes and
the high carb athletes
had the same amount of muscle glycogen.
And that it followed the same
pattern even in recovery.
So after the three hour run,
and then also two hours into recovery,
muscle glycogen was all the same.
– But the difference between them
was because the keto adapted athletes
were burning fat at twice the rate,
providing 80 to 90% of the fuel
during their endurance run at race pace.
So as Amy said, they ran them,
had them run on a treadmill three hours,
in the lab.
– In the lab, staring at a blank wall.
– The Keto adapted athletes mobilized
muscle glycogen at the same rate.
But they, it appears
that they recycled it.
They didn’t burn it all
the way to CO2 and water.
So it’s like, you know,
basically recycling that same carbon,
so they didn’t need to
eat a lot of carbohydrate
in their diet in order to regenerate
and maintain muscle glycogen stores.
But from a parental perspective,
how many ketogenic
enhanced diet performance,
one thing that the endurance athlete
tells is that when they’re keto adapted
they’re much less likely to hit the wall.
That is how the central nervous system
begins to shut down saying
you aren’t providing
me enough glucose to keep
my brain functioning.
So A, they can go for
longer periods of time.
And it appears to be
that because the brain
can function very well on ketones,
and is not glucose dependent.
And so for events lasting longer
than three or four hours,
when normally, again a
full iron man triathlon,
they have to eat continuously during
the running and the cycling
legs of those events.
One was that the athletes find
they need to eat far less calories
in the race in order
to sustain performance.
So that’s one aspect that’s beneficial.
And the other is what we
call power to weight ratio.
That many athletes find, no
matter how hard they train,
they can’t train themselves down
to an ideal, low level of body fat.
Say under 10%.
And for some athletes getting under 10%
is really important in terms
of the power to weight ratio.
And they find that when they
adapt a well formulated,
ketogenic diet they’re
better able to achieve
that optimum percent body fat
that optimizes the ratio of muscle
to muscle weight to body fat weight.
And again for those athletes,
oftentimes they will train on a high fat,
low carb diet to get ideal
body composition down.
And then they can add back what they call
strategic carbs, either
immediately before,
or during an event in order
to optimize glycogen as well.
And again this tends
to be athlete specific.
Each athlete needs to have some guidance,
but their own experience in figuring out
what works best for them
in terms of the degree
of carbohydrate restriction,
and the amount of carbs
that can be used strategically
to maintain optimum performance.
– Yeah, and I think we’ve talked
a lot about resistance training,
or endurance training, but I think
resistance comes up a lot too.
I think there was a study recently,
I hope I’m not miss remembering this.
I think it was out of
Donovan and Stephen’s group,
or he was involved in it somehow.
But they looked at 10
weeks of western diet
compared to a ketogenic diet,
and similar gains in terms of strength
and power during that time.
And also similar losses
of body fat and muscle
gain between the two groups.
So it doesn’t appear to
impair performance in any way.
– And not to get too
far ahead of the data,
Professor Volek at OSU is,
has completed the data collection
from a study they did with a high carb
versus a ketogenic diet in a group
of student athletes where they did
a intensive resistance training program.
And hopefully those data
will be reported this year.
But it will I think, emphasize the benefit
in terms of resistance training,
and maintaining lean body mass
and optimizing power to weight ratio.