[Rhonda]: But, you know, people are asking about things, like even supplements.
And I think, like, you know, again, you've answered that we don't, you know...
You know, are you taking fish oil?
Is it a fatty acid?
I mean maybe...
There's lots of things here because that is, you know...
So if you're taking a fish oil supplement, then what do you think?
That's different than taking, for example, vitamin D?
[Satchin]: Well, it's a question of...
I like to compare this to, say, physical activity.
Somebody is completely sedentary.
For that person going for a walk, whether it's in the morning or evening or midnight
doesn't matter because this person is getting some benefit of physical activity.
Similarly, if somebody is very low on vitamin D or needs that fish oil supplement, then
what time the person takes doesn't matter because that deficiency is getting corrected.
[Rhonda]: Yeah, that's true.
[Satchin]: So that's true.
But then if someone now dials it slightly higher and says, "Well, you know, I want to
have this protein drinks that's 25 grams of protein after my exercise late at night.
Is it okay?"
Then that's where I'll say, "Well, then that's going to affect your gluconeogenesis and muscle
recovery.
And maybe if you have done a very strenuous exercise, if you're training for, like, Ironman
or something like that, yes, you have to have that to recovery.
[Rhonda]: Yeah.
So that was actually a question I think people were...
Someone was asking about weight training at night, if that would counter.
If they, you know, eat late at night after weight training, if that would counter.
And I think that's kind of pushing it a little bit.
[Satchin]: Yeah, that's pushing a little bit.
[Rhonda]: Which is kind of what you're saying.
[Satchin]: And, again, it depends on your training schedule and other stuff, what do
you want to get the most out of it.
Like, for example, if you're used to training late at night and having that protein and
carb drink right after that, what if you do a little self-experimentation and move that
to, say, 5:00 or 6:00 and see whether it actually helps you do one extra pushup or to go for
another five minutes, or is it actually compromising your performance.
So, again, it's very personal.
And then some of these very kind of athletes who are pushing themselves to the limit, they
want to squeeze the last drop of performance out of it.
And for them I think self-experimentation is the best way because there is no way we
as scientists, we can do that kind of study in our labs with a number of subjects who
are as competent as them, and then controlling for everything.
So it would be very difficult.
[Rhonda]: But you did show in one of your animal studies that a shorter feeding window
for these animals, like, for example, nine hours...or it was eight or nine hours.
[Satchin]: Eight to nine, both of them.
[Rhonda]: Endurance...
[Satchin]: Endurance went up.
[Rhonda]: ...performance went up.
So you do have some evidence of being able to squeeze the last drop of performance maybe.
[Satchin]: Yeah.
So that way you clearly see endurance went up.
And the reason why we did that experiment was we thought, "Well, if the mice are feeling
fasted for a long time, will their athletic performance or muscle performance go down?"
Because our worry was their performance, athletic performance, might go down.
And in that way it might be harmful for some people for whom physical activity is needed.
And, for example, many shift workers, they need that physical performance.
[Rhonda]: Right.
[Satchin]: That's why we did it.
[Rhonda]: And we realized that their grip strength, which is similar to how much weight
a person can lift, that did not change, that stayed the same.
But the endurance, being on the treadmill for a long time, that actually significantly
increased, and in some cases it doubles.
[Rhonda]: Doubles?
[Satchin]: Yeah.
[Rhonda]: I've noticed this in myself.
I've done, like, an eight or nine-hour eating, you know, schedule and the next day...
So if I'm fasting for a longer period, the next day I go for a run in the morning and
my endurance is...
And this is, I mean, we're talking like five or six times, maybe seven times I've noticed
it.
[Satchin]: Yeah, yeah.
[Rhonda]: I mean it's a clear pattern.
[Satchin]: Yeah.
[Rhonda]: My endurance is dramatically improved.
I mean it's incredible, like, I just can keep running.
Like, whereas usually I'm tired and I reach the mark where I'm like, "Okay, this is it,
finally I'm getting"...
You know, you kind of sprint to the end and now I just keep going.
[Satchin]: Yeah.
No, we see that.
There are many people who have given us this feedback that their endurance does go up.
And then what is interesting is, again, their endurance improves, and then once in a while
they say, "Well, I can go back to 12 hours," and then immediately they see the reversal
of that endurance.
[Rhonda]: Right.
It does, exactly.
It totally reverses, yeah.
[Satchin]: Yeah.
[Rhonda]: You know, I know there's been some recent studies coming out in the last year
or so where exogenous ketone bodies have been given to endurance athletes and it improved
their endurance capacity.
Which makes sense because endurance heavily relies on mitochondria.
Right?
So, I mean, it completely...
I mean if that's actually part of the mechanism with the time-restricted eating in terms of
a longer faster period one would presume would have higher levels of ketone bodies.
[Satchin]: Yeah, we do see they have a slightly higher level of ketone bodies.
[Rhonda]: So it makes sense.
[Satchin]: Yeah.
[Rhonda]: Whereas...
Well, I don't know what exactly you're doing with the grip strength, but, you know, it
depends on whether or not if you're pushing them to a high enough intensity where they're
becoming glycolytic or not.
I don't know.
[Satchin]: Yeah.
So, again, we don't know where the dynamic range of that particular assay and we can't
ask questions to mice.
So this is where people who are actually lifting weights are doing something, a very different
kind of exercise.
Endurance exercise versus intense exercise, those are very different.
Maybe they can give us feedback to see what happens.
[Rhonda]: Now in your study wasn't there improved lean muscle mass?
[Satchin]: Yes, we did see lean muscle mass improvement only on mice that were given standard
diet, not on high fat diet.
[Rhonda]: Okay.
[Satchin]: The high fat diet fed mice...
[Rhonda]: Yeah, I wouldn't expect for them.
So they were given...so the mice that were given the normal, sort of healthier diet.
[Satchin]: Yeah.
[Rhonda]: What was their eating schedule?
[Satchin]: They were eight to nine hours.
[Rhonda]: So it was a shorter time window they were eating?
[Satchin]: Yeah, yeah yeah.
[Rhonda]: They had increased lean muscle mass.
Now is that something, like, do you know why that is?
Has that been looked at?
[Satchin]: We actually don't understand that, that's another thing.
But we do see there is an increase in PGC-1 expression in muscle, so there might be an
increase in mitochondria function.
But surprisingly in the same mice we saw there is less glycogen in muscle.
And that's kind of counterintuitive.
You might think that, "Well, the muscles may be loaded with glycogen, so that's why their
lean mass went up."
But at the same time what we think is maybe, because they have less glycogen, we know that
if the muscle has less glycogen than after normal activity, then glycogen may be completely
depleted.
And when they eat, they have a much better feeding response.
So that means a much better glycogen synthesis response.
So they may be making and breaking glycogen, making and breaking triglyceride on a daily
basis, or protein on a daily basis.
So in that way I think they may be maintaining much better muscle health.
Because they're also going through some gluconeogenesis, they're breaking down some protein.
So maybe some of the structural proteins that get modified and maybe they get damaged, they're
kind of getting cleansed, they're getting cleaned out of the system by this eating and
fasting rhythm.
So, again, it's all speculation, so we have to go back to the muscle samples.
[Rhonda]: Yeah.
You have the data, you just don't know the mechanism.
[Satchin]: We don't know the mechanism.
[Rhonda]: But people are very interested.
I mean increasing lean muscle mass is hard to do and there's a lot of huge interest in
it.
[Satchin]: Yeah.
[Rhonda]: Huge interest.
[Satchin]: No, actually we have been seeing this reproducibly now in multiple strains
of mice.
And it happens with a balanced diet.
So this is where the nutrition quality does...
[Rhonda]: Play a role.
[Satchin]: ...play a role.
[Rhonda]: Which makes sense.
[Satchin]: Yeah.
[Rhonda]: Yeah.
[Satchin]: So we can't expect people to eat the same fatty food and expect lean muscle
mass.
[Rhonda]: Right, yeah.
So there's a nutritional component to it in addition to eating within a restricted time
window.