Video summary
Dr. Peter Attia addresses the current trend of demonizing meat consumption and limiting amino acid intake to prevent chronic activation of the mTOR pathway, arguing that this perspective creates a dangerous confusion between acute and chronic metabolic states. He emphasizes that mTOR is the body's most critical sensor for amino acids like leucine, lysine, and methionine, which are essential for achieving anabolic states necessary at certain times in life. Unlike mice models where tissue-specific activation can be measured, humans lack a tool comparable to hemoglobin A1c for glucose integration to monitor mTOR activity across different tissues such as muscle versus the liver. Consequently, Attia contends that limiting amino acids is counterproductive and leads to sarcopenia, or age-related muscle loss, rather than providing longevity benefits through restriction alone. The discussion shifts to practical protein consumption strategies, where Attia challenges the notion that consuming three to four servings of 25 to 50 grams of protein daily results in a constant spike in mTOR activity throughout the day. He explains that free amino acids remain in circulation for only a short duration, and individuals spend roughly 14 hours each day without eating, during which time amino acid levels drop significantly even for those consuming high amounts like 1.8 to 2 grams per kilogram of body weight. Attia notes his own history with extreme fasting protocols, including quarterly seven-to-ten-day fasts and monthly three-day fasts inspired by David Sinclair's work at Harvard, but he has since abandoned these practices due to the difficulty in maintaining muscle mass while staying fit and performing well physically. A significant portion of the conversation focuses on the drawbacks of time-restricted feeding compared to direct caloric restriction or dietary restriction. Attia points out that clinical trials show no additional benefits from time restriction beyond simple calorie reduction, debunking the idea that hunger signals during fasting windows offer unique advantages over small amounts of satiation throughout the day. The primary issue with strict time restriction is the reduced likelihood of consuming adequate protein within a compressed window; for instance, eating 180 grams of protein in one sitting or spreading it across too many tiny servings fails to optimize muscle synthesis because amino acids are wasted via gluconeogenesis if not balanced correctly between roughly 25 and 50 grams per serving. To mitigate these issues while maintaining the compliance benefits of time restriction for some patients, Attia suggests a hybrid approach that prioritizes protein intake regardless of timing constraints. He recommends starting the day with a low-calorie protein shake containing about 200 calories made from ingredients like cashew milk and frozen berries to ensure an early amino acid dose without breaking a fast's caloric goals. This strategy is particularly important for untrained individuals who exercise in the morning, as having amino acids available closer to training sessions helps prevent muscle loss that often occurs when feeding windows are delayed until evening. Ultimately, Attia concludes that while time restriction is conceptually easy and compliant-friendly, it must be carefully managed with deliberate protein dosing—ideally four servings of 45 grams—to avoid the pitfalls of sarcopenia and ensure optimal metabolic health.
Read the full video transcript
what are your thoughts on this current
movement at the moment which is people
avoiding and sometimes demonizing meat
consumption because of activating the
mtor pathway
yeah I think there's a bit of a
confusion between chronic activation of
the mtor pathway and acute Activation so
we do need mtor to be active sometimes
right I mean mtor is the most important
amino acid sensor we have in our body
and if we want to be in a in an anabolic
State at some times which we do it's
going to have to be activated right in
fact I would argue that the three most
important amino acids leucine lysine
methionine will mtor is the leucine
sensor right I mean leucine and mtor
were sort of made for each other this is
very different from the metabolically
ill person whose mtor level is probably
chronically elevated there's also an
issue with tissue specificity and again
part of the challenge here is in humans
we have no way of measuring this so we
can measure this stuff in mice you can
sort of look at mtor activation and
muscle versus liver versus some other
tissue in humans we can't do any of this
we don't have what David sabatini refers
to as an mtor integrator a signal
integrator so the sort of the way that
hemoglobin A1c is an integrating
function of average glucose right it
integrates glucose level over the
previous three months roughly we don't
have a tool like that to measure mtor
activity so
um again I think that the the belief
that we need to limit amino acids to
limit mtor activity is is kind of a
backwards way to think about it what
that's really going to do is create a
situation of sarcopenia which uh muscle
like loss of muscle as we age okay yeah
surely though if people are consuming
three to four servings of
25 to 50 grams of protein per day is
that not just going to continue to just
Spike M toward does that not end up
netting out at mtol just being elevated
throughout the day not necessarily I
mean you have to remember the the
um the duration that you know free amino
acids stay in your circulation is pretty
low
um you're also probably still spending
12 to at least 14 hours a day when
you're not eating
right so even so so I'm someone who
probably takes a lot of effort to
consume you know
1.8 to 2 grams of protein per kilogram
of body weight and that's going to be
spread out over three to four meals but
there's probably still 14 hours a day
when I'm not eating anything and during
that period of time those amino acid
levels are going to be really low
I heard about you doing some very
extreme fasts over the last few years
talk to me about those yeah I don't do
that anymore but I used to do a lot of
fasting for many years I would you know
do a seven to ten day fast quarterly and
a three-day fast monthly
that's intense
that seems intense yeah me you know I'm
someone that's done intermittent fasting
I sat down with David Sinclair
four and a half years ago I think in his
office at Harvard uh and you know when
David first came onto the scene which
was the first time I'd really really
heard intermittent fasting as being
pushed as a longevity lever uh I thought
this is great like you know it's
something that I can do it's for the
lazy Among Us it actually makes eating
food easier because we've managed to
um reword skipping breakfast as doing
intermittent fasting but
I found it incredibly difficult to blend
staying fit staying muscular and doing
intermittent fasting I really really
struggled to make that work
um what have you first off why have you
changed your approach to intermittent
fasting I know that you've gained a ton
of muscle recently
um and how have you worked in blending
your understanding of intermittent
fasting and its positive benefits with
the fact that you want to look good feel
good perform well yeah so again I still
think going back to kind of what are the
three ways that you can reduce caloric
intake you can you can calorie restrict
directly so just track and reduce
globally you can dietary restrict which
is pick certain elements within the diet
carbs fat whatever restrict or you can
time restrict create a smaller and
smaller window in which to eat
um the biggest drawback of that final
strategy which again is a viable
strategy but the biggest drawback of it
in my opinion is the the reduction in
protein intake
so this has been borne out in the
literature so we've seen we've seen
clinical trials that have documented
this that first and foremost the time
restricted feeding within that 24-hour
period doesn't seem to produce any
benefits above the caloric restriction
that it brings that's a very important
caveat okay it's just meaning there is
nothing magical about the time
restriction beyond the calories that are
being restricted wow okay so the hunger
signal that people get which is those of
us that have taken like the Sinclair red
pill this is a signal that I'm hungry
this is homies it's happening this is
discomfort this is good for me
has no different impact than small
amounts of satiation throughout the day
with there's nothing that has been
measured or documented in any clinical
trial that suggests that that is
beneficial over the clerk restriction in
other words if you're going to eat 2 000
calories spread out over 12 hours or
you're going to eat 2 000 calories
spread out over six hours where you're
you know calorie you know your time
restricted feeding for 18 hours
we're not seeing any difference wow now
and now that's not here's what's
interesting that's often not what
happens
so what more likely happens is the
person who calorie restricts
um has an easier time Believe It or Not
maintaining muscle mass than the person
who time restricts why
probably for two reasons uh although
this hasn't been fully teased out in the
in the data because they're not tracking
it this closely but my
my impression is that when you time
restrict you're just less likely to eat
as much protein
and secondly as you kind of alluded to
earlier
um it's a delicate balance to get the
right amount of amino acids into the
muscles you can't have too much and you
can't have too little
so what you don't want to do is waste
for lack of a better word your amino
acids down a gluconeogenic pathway where
they're basically being used as glucose
substrate what would cause that to
happen either too much or too little so
it wants too much and what's too little
yeah sort of 10 to 20 grams of protein
the liver is going to preferentially
take that and use it as glucose and
anything over about 50 grams the liver
is going to say I'm going to take that
excess and also make it glucose so let's
just say your number is 180 grams of
protein per day eating 18 servings of 10
grams a day not going to achieve optimal
results having one serving of 180 also
Knuckles I've tried both yeah yeah
um so that person really probably ought
to be doing four servings of 45 right so
you're saying for most people it seems
like roughly a sweet spot is 25 to 50
grams per serving exactly right so in
this regard and that that time
restricted feeding guy has a really hard
time doing that if he's going to be
deliberate about that how big is the gap
when does a feeding window stop great
question probably about three or four
hours so it's basically impossible
for the time restricted feeding person
yes unless they're willing to eat
protein outside of their window right
okay which if you are a dogmatic around
if you're dogmatic it becomes very
difficult correct but if you're if you
understand that there and what we do
with our patients who who want to do
time restricted feeding because I think
it's the easiest one to do yep like I
would agree it's the easiest one
conceptually to do it's the easiest one
to be compliant with so what we would
say is look it's just about the calories
so I still want you to have a low
calorie protein shake in the morning
where you're going to have 200 calories
of a protein shake that's basically just
protein some you know cashew milk and a
few frozen berries
um but at least you got that protein
dose in the other thing that I would say
leads to what we experience clinically
as a lot of people losing muscle mass
when they do this is a lot of people
exercise in the morning but their
feeding window is in the evening
so now they're creating a little bit of
a gap especially if they're untrained
it's less less of an issue in a trained
individual but in an untrained
individual we do see some benefits to
having the amino acids uh restored in
Greater proximity to the training every
single loaning for over three years now
I've started my day the exact same way
which is with element in Walton element
contains a science-backed electrolyte
ratio of sodium potassium and magnesium
and it is the best hydration drink that
I've ever found it tastes fantastic it's
super refreshing orange is just the most
OP flavor in the world it's absolutely
phenomenal and it helps to play a
critical role in reducing muscle cramps
and fatigue it regulates your appetite
it optimizes brain health and it helps
curb Cravings they're also the exclusive
hydration partner to Team USA
weightlifting and rely on by tons of
Olympic athletes and everyday High
performers all around the world also
there is a no BS no questions asked
grief and policy where you can buy a box
completely risk-free and if you do not
like it for any reason reason they will
give you a refund during an unlimited
duration and you don't even need to
return the box that's how confident they
are that you'll love it element are
giving away a free sample pack of all
eight flavors with your first box if you
go to the link in the description box
below or drink lmnt.com
MW that's drink
lmnt.com
MW what's happening people if you
enjoyed that then press here for the
full unedited episode and don't forget
to subscribe
[Music]