How Fat Loss Works - Episode 2: Fat Metabolism
Summary
TLDRThis educational video delves into fat metabolism, explaining how fats are digested and transported in the body as chylomicrons through the lymphatic system into the bloodstream. It clarifies that fats, being hydrophobic, must be repackaged to traverse hydrophilic bodily fluids. The video distinguishes between fat metabolism during caloric surplus and deficit, emphasizing that while insulin affects fat storage, it isn't necessary for it. It also highlights the body's preference for fat as an energy source to spare glucose and muscle glycogen, especially during a caloric deficit, and discusses the impact of high-fat versus high-carb diets on fat oxidation and storage.
Takeaways
- 🔍 Fat metabolism is a complex process involving digestion, transportation, and storage of fatty acids in the body.
- 🌀 Fat digestion primarily occurs in the small intestine, specifically in the duodenum, and is different from carbohydrate and protein digestion.
- 🚛 Chylomicrons are large globules of fat that transport dietary fat through the lymphatic system into the bloodstream.
- 🧬 Fat is hydrophobic, meaning it does not mix with water, and thus must be packaged in chylomicrons to travel through the body's hydrophilic environment.
- 🔄 The process of fat entering and exiting cells involves being repackaged and unpackaged to cross cell membranes.
- ⚡ High rates of fat oxidation are associated with a caloric deficit, where the body burns more fat for energy.
- 🔄 In a caloric surplus, particularly with a high-fat diet, the body both burns and stores more fat, with the net balance determining fat loss or gain.
- 🍽 The type of diet (high carb vs. low carb, high fat vs. low fat) influences the rate of fat oxidation and the amount of fat stored.
- 🏋️♂️ During exercise, especially high-intensity activities, the body prefers to use glycogen over fat to spare energy for quick, intense bursts.
- 💊 The body does not require insulin to store fat as body fat, contrary to some common beliefs.
- 🔄 In a negative energy balance, the body liberates fatty acids from adipose tissue to meet energy demands, prioritizing blood glucose stability and sparing muscle glycogen.
Q & A
What is the main topic of the video script?
-The main topic of the video script is fat metabolism, specifically discussing how fat moves and fluxes in the body depending on different states such as caloric surplus or deficit, and the role of insulin in fat storage.
How does fat digestion differ from carbohydrate and protein digestion?
-Fat digestion is different because it mostly occurs in the small intestine, particularly in the duodenum, and involves packaging fat into chylomicrons, which are large globules of fat that pass through the lymphatic system before entering the bloodstream.
What are chylomicrons and what role do they play in fat metabolism?
-Chylomicrons are large globules of fat that are formed during fat digestion. They play a role in transporting dietary fat from the digestive system into the bloodstream via the lymphatic system.
Why are fats considered nonpolar and how does this affect their interaction with water?
-Fats are considered nonpolar due to their hydrophobic nature, meaning they do not mix well with water. This is because they tend to associate with other hydrophobic substances, leading to the formation of separate phases when mixed with water.
How does the body transport fat across different barriers within the body?
-The body transports fat by packaging it into vehicles like chylomicrons and very-low-density lipoproteins (VLDLs) to move through hydrophilic mediums such as the bloodstream. Fat must be unpackaged to cross membranes and repackaged on the other side.
What is the storage form of fat in the body and how is it utilized?
-The storage form of fat in the body is triacylglycerol, which is a glycerol molecule with three fatty acid chains. It is utilized by being broken down into individual fatty acids and glycerol, which can be used for energy or converted into glucose through gluconeogenesis.
Does insulin play a role in fat storage in the body?
-Insulin is not required for fat storage in the body. The video script clarifies that a common misconception is that insulin is necessary for fat to be stored as body fat, but this is not the case.
How does a high-fat, low-carbohydrate diet affect fat metabolism?
-A high-fat, low-carbohydrate diet leads to increased fat oxidation due to the higher availability of fat as a fuel source, but also results in increased fat storage because of the lack of insulin, which is a storage hormone.
What is the process called when the body converts carbohydrates into fat?
-The process of converting carbohydrates into fat is called de novo lipogenesis, which primarily occurs in the liver and results in the production of very-low-density lipoproteins (VLDLs).
How does the body prioritize energy sources during a caloric deficit?
-During a caloric deficit, the body prioritizes fat as an energy source to spare muscle glycogen and maintain blood glucose levels, leading to increased fat oxidation and potentially decreased fat storage depending on the diet's macronutrient composition.
What determines whether the body gains or loses fat according to the script?
-According to the script, the net balance of energy intake versus energy expenditure determines whether the body gains or loses fat, regardless of the macronutrient composition of the diet.
Outlines
🔍 Understanding Fat Metabolism
The speaker begins by introducing the second part of a series on fat loss, focusing on fat metabolism. They briefly touch on fat digestion, which mainly occurs in the small intestine, specifically the duodenum. Fat, being nonpolar, is packaged into chylomicrons, large globules that travel through the lymphatic system before entering the bloodstream near the clavicle. The chylomicrons can then be delivered to various tissues, such as the liver and adipose tissue, where they can be repackaged into different lipoproteins or broken down for energy use. The speaker emphasizes the hydrophobic nature of fat and its need to be packaged for transport through hydrophilic mediums like blood and lymph.
🚀 Fat Digestion and Storage
This paragraph delves deeper into the digestion and storage of fat. The speaker explains that fat is stored in the body primarily as triacylglycerols, which are composed of a glycerol molecule and three fatty acids. When the body requires energy, these triacylglycerols are broken down into glycerol and fatty acids. The glycerol can be used for gluconeogenesis in the liver, while the fatty acids can cross cell membranes and be repackaged for transport to tissues where they can be used for energy. The speaker clarifies that fat does not require insulin for storage, contrary to common belief, and that the net balance of fat intake and expenditure determines fat loss or gain.
🍽️ Macronutrient Intake and Fat Metabolism
The speaker explores how different macronutrient intakes affect fat metabolism. They use examples of high-fat, low-carbohydrate meals versus high-carbohydrate, low-fat meals to illustrate the impact on fat oxidation and storage. In a caloric surplus with a high-fat diet, there is an increased rate of fat oxidation but also increased fat storage due to the high intake of fat. Conversely, in a caloric deficit with a high-carb diet, fat oxidation is lower, and less fat is stored because there is less fat intake. The speaker highlights that while insulin levels can influence the storage of fat, the overall energy balance is the key determinant of fat loss or gain.
🔄 Energy Balance and Fat Flux
The final paragraph addresses the concept of energy balance and its role in fat metabolism. The speaker explains that in a negative energy balance, the body will liberate fatty acids from adipose tissue to meet its energy needs, as it seeks to maintain blood glucose levels and spare muscle glycogen. This process is influenced by the type of diet, with high-fat diets leading to more fat oxidation and storage, and high-carb diets leading to more carbohydrate oxidation and less fat storage. The speaker concludes by emphasizing that the body's primary goal is to maintain energy balance, and that the actual amount of fat lost or gained is dictated by this balance, not solely by the diet's macronutrient composition.
Mindmap
Keywords
💡Fat Metabolism
💡Chylomicrons
💡Hydrophilic and Hydrophobic
💡Lymphatic System
💡Triacylglycerols
💡Fatty Acids
💡Insulin
💡Caloric Surplus and Deficit
💡De Novo Lipogenesis
💡Energy Balance
Highlights
Fat metabolism is a complex process involving digestion, transportation, and storage.
Fat digestion primarily occurs in the small intestine, particularly the duodenum.
Fats are packaged into chylomicrons, which are large globules that travel through the lymphatic system.
Chylomicrons eventually enter the bloodstream near the clavicle area.
Fats must be repackaged to move through hydrophilic mediums like blood.
Fats are broken down and repackaged in the liver into various lipoproteins.
Fats are also stored in adipose tissue and can be used by other tissues for energy.
Fat must be unpackaged to cross cell membranes and repackaged once inside.
Triglycerides are the storage form of fat and are composed of a glycerol molecule and three fatty acids.
Glycerol can be used for gluconeogenesis or repackaged into another triglyceride.
Fatty acids can be oxidized for energy or repackaged and stored.
Fat storage and oxidation rates depend on insulin levels and dietary macronutrient composition.
High-fat, low-carb diets can lead to increased fat storage despite higher fat oxidation rates.
Insulin is not necessary for fat storage, contrary to popular belief.
Low-fat, high-carb diets can result in less fat oxidation but also less fat storage.
De novo lipogenesis is a process where carbohydrates can be converted to fat, but it is not a major contributor to fat storage under normal conditions.
Energy balance, not insulin levels, ultimately determines whether fat is gained or lost.
In a negative energy balance, the body liberates fatty acids from storage to meet energy demands.
In a positive energy balance, fat is stored in adipose tissue due to excess caloric intake.
Transcripts
[Music]
hey guys welcome back to the second part
of my series about how fat loss works
part 2 is fat metabolism okay so I don't
want to go too much into digestion and
especially beta-oxidation today which
we'll talk about later but I do want to
talk about kind of overall how fat moves
and fluxes in the body depending on what
state you're in okay so fat digestion is
much different than carbohydrate and
protein a lot of it occurs in the small
intestine mostly in the duodenum and
they're actually packaged into these
these these kind of fat I want say
vehicles but they're called chylomicrons
and they're these big globules of fat
basically so fat is what we call
nonpolar so you ever say heard people
say oil and water don't mix right well
oil is fat and if you take oil put it
into water it will all it will start up
and maybe start out as different
droplets but it'll eventually all come
together right like you know it will
it's what's called hydrophobic and
hydrophobic things want to associate
with other hydrophobic things so what
you'll have is there's these big
globules what they're called
chylomicrons and they're just big
globules of fat and they go through your
what's your called your lymphatic system
and they actually end up dumping out
from digestion into the bloodstream
somewhere up around your clavicle area
so once they're in the bloodstream they
can then go to different tissues like
the liver where they can be repackaged
into like mmm they be broken down and
repackaged into like vldls LDLs hdls
some other things and they can also go
to adipose tissue and then go skeletal
muscle and then go to other tissues like
heart and
you know some any other tissue that the
burns fatty acids so similarly it now
keep in mind whenever you cross a
barrier with fat okay what happens is it
has to be packaged because the
bloodstream and all the other kind of
the fluid parts of your body are
hydrophilic so they're they're mostly
water so they have to be packaged into
something that can move through these
mediums all right and then to get across
the membrane they have to be unpackaged
taken through the medium and then
repackaged okay so in the case of kala
microns for example in the intestine the
fat you eat goes through your digestive
process and then it gets to the duodenum
you have pancreatic lipase --is that
then break down those most the fat sweet
our trial glycerides which we'll talk
about more in a minute so they they
break down these triglycerides they go
through the intestinal lumen they come
out in the lymphatic system or they go
through the intestinal lumen repackaged
and then go through the lymphatic system
into the bloodstream okay now these
chylomicrons when they get to let's say
adipose tissue they're then again broken
down by life phases okay into individual
fatty acids and then they are then they
can cross the membrane they can cross
the membrane of the adipose cell all
right they can go into that fat cell and
then they're repackaged again in to try
so glycerides okay so and that's going
to happen in the liver and muscle to
whenever they just come trying to ki let
you keep in mind whenever fat crosses a
barrier it has to be it whatever package
it's being delivered in it has to be
unwrapped and then once it's in the
inside whatever membrane it's going to
its rewrapped and repackaged unless
those fatty acids are then burned for
specific reasons that are oxidized so if
we so we know that Kalla microns can
goes is all these different tissues and
be delivered now let's look a little bit
more at
how fatty acid or how triacylglycerols
are constructed this is your storage
form of fat it's also how you eat most
of your fat most of the fat you consume
is in the form of tri so glycerides why
do we call it a try so glyceride simple
tri 3 fatty acids acyl acyl stands for a
long carbon hydrogen chain okay so try a
SIL glyceride glyceride is a glycerol
molecule okay so over here we have and
this is how they're stored adipose
mostly as as tri so glycerides alright
just it's literally your your fat cells
are literally just packed full of tri so
glycerides
and it's your storage unit alright so
you have your these are tri so
glycerides you had this glycerol head
here okay right now if like for example
we're talking about adipose and we're
gonna get to these situations in a
minute but you're in a situation where
you need to liberate fatty acids and get
them to another tissue let's say muscles
working hard muscle needs fatty acids to
burn for fuel well remember they're
gonna cross the barrier they're gonna go
out of the cell so they have to be
unpackaged so they can cross that
membrane and then repackaged okay so
what happens is there's a process that
cleaves this glycerol this glycerol
molecule okay so this leaves right and
you just get a glycerol molecule
terrible handwriting and that glycerol
can actually then be used for what's
called gluconeogenesis or it can just be
converted - it can be repackages another
tri so glyceride with other fatty acid
molecules okay they get a lot of stuff
in metabolism gets recycled but it also
can be used for for producing glucose
through gluconeogenesis in the liver so
you have whenever you have high rates of
fat oxidation or you're burning a lot of
fat you're also having a lot of glycerol
going to
liver because you're producing a lot of
glucose through gluconeogenesis because
it's usually when you're in a caloric
deficit so though just keep in mind
those two things usually go hand in hand
so now you've cleaved this glycerol
molecule and now you're going to be left
with three fatty acids it's actually the
way it works is the way it works
typically is actually when you when you
go through life pollicis you have first
a you'll have a reaction where there's a
diocese silver lipase where you have one
fatty acid a glycerol head and then two
fatty acids and then those that that two
fatty acids are then broken down and
then you have three fatty acids so it
goes two and one and then and then the
one that has two will be separated so
you're left with three fatty acids from
every triacylglycerol these fatty acids
can now cross this membrane out of the
cell can then be repackaged head to the
muscle and they can be used for energy
or they can go to the liver and they can
be repackaged and used for energy like
any any any tissue can do this all right
now that we kind of understand the
basics of how tri so glycerides and
fatty acids and those sorts of things
work and I do want to be specific you
don't always have to repackage fatty
acids when they're in the bloodstream
there are certain amount of fatty acids
that do stay in the bloodstream but for
the most part for transport and storage
they're packaged this tri so glycerides
so for our purposes that's how we're
going to think of it now let's talk
about what happens during different
situations okay let's say you ate
you were in a caloric surplus and you
ate a high-fat low-carbohydrate meal so
we have high fat low carb all right well
you're going to get a lot of these guys
right a lot of these chylomicrons right
because you ate high fat
all right but it was low-carb so you
don't have a lot of insulin insulins of
storage hormone so you're gonna have low
insulin so you're not you're burning
you're going to be burning a lot of fat
during this time okay so you're gonna
have an creat increase fat oxidation all
right even though you're in the surplus
you're still gonna be burning a lot of
fat because that's the fuel you're
providing if you're on a high-fat diet
but you're also going to have a lot of
fat storage okay so your so some of
these are going to go here there's gonna
be a lot of flux into adipose and
contrary to what a lot of people say you
don't need insulin to store fat as body
fat I'll say it again you do not need
insulin to store fat that's body fat
okay so yes you are burning more fat
you're also storing more fat the net
balance will be what we talked about
last video if you haven't seen the last
week I'll go back and encourage you to
go back and look at the net balance is
going to determine whether the overall
effect is fat loss or fat gain so if
you're in a caloric surplus the flux of
fat into adipose is going to be greater
than the amount you're burning even
though the rate at which you're burning
fat is going to be higher than if you
were on a high carb diet let me give you
another example so let's go with a high
carb diet relatively high carb diet
relatively high carb diet but during
caloric restriction so we just gave the
example of a high fat diet during a
caloric surplus let's look at a low fat
high carb diet during a caloric deficit
so so we're in negative energy balance
so we have high carb low fat okay that
means we're gonna have higher levels of
insulin
but we have less fatty acids right so we
had all those column icons coming in
well if you're on a low-fat diet you
don't have nearly as much okay now you
are not going to you're going to have
decreased fat oxidation the rate of fat
oxidation is going to be lower but
you're also going to be storing less fat
because you're not eating as much fat
okay
now people may say well you can store
carbohydrates as fat technically yes but
that's called de novo lipogenesis so
we'll just call and that happens in the
liver and that's called dnl de novo by
PO Genesis but the rate at which de novo
lipogenesis occurs is is that actually
winds up an adipose tissue so if we look
at glucose there goes that's in the
liver and it goes through de novo
lipogenesis and then comes out as well
it actually be like vldls and LDLs and
actually ends up getting stored in
adipose it is a very very very small
amount unless you are chronically on a
very high carb diet very low-fat de novo
lipogenesis is not going to account for
a significant amount of fat storage okay
now what is going to happen is since you
are higher insulin you're going to be
burning more carbohydrate less fat so
the fat that you do eat is more likely
to be stored as fat but since there's
less overall fat the how much actual
body fat you gain or lose is once again
going to be dependent on your total
energy balance okay so just because
insulin is high doesn't mean you're
storing a ton of fat because if you're
not eating much fat there's just not
that much fat to store okay now it does
mean that the fat you eat is more likely
to get stored so let me give you an
example let's just use arbitrary numbers
for a moment so let's say you're eating
100
of fat okay I'm sorry let's say 200
grams of fat that means your oxidation
is going to be way up fat oxidation carb
oxidation is going to be way down and
insulin is going to be low as long as
carbohydrates are low okay but you're
also going to be storing a lot of fat so
let's say we have 200 grams of fat we
eat all right we have low insulin
because it's low carbohydrate we have
highlights of fat oxidation because
we're eating a lot of fat we have low
bonds of carbohydrate oxidation because
we don't need to because there's not
that much carbohydrate available but
we've also got increased fat storage
because it's a very high calorie if
we're in a positive energy balance we're
gonna restore a lot even if we're in a
negative energy balance we'd be storing
a lot the difference if you're in a
negative energy balance is that the
amount that you are oxidizing will
exceed the amount you were storing I'll
say it again and a negative energy
balance the amount you're oxidizing will
exceed the amount you're storing so
let's say of this you're oxidized let's
say these are both negative energy
balances in this example all right
negative energy balance let's say you
burn I'm just using 170 grams and you
store 30 okay all right well you're in a
in a negative energy balance you're
gonna lose fat in that scenario but now
let's go to a high carb low fat all
right now you didn't store it you didn't
store much herbs yeah you didn't store a
great proportion of the fat you took in
you store like less than a sixth of it
because insulin was low right but let's
look at what happens if we eat 40 grams
of fat so we have decreased fat
oxidation let's say we ate that and then
like 200 grams of carbs but we're still
in the negative energy balance the
increased fat oxidation increased
carbohydrate oxidation but we have
decreased overall the
storage absolute fat storage but the
percentage of the fat you ate is going
to be stole more stored because of
increased insulin let me show you what I
mean so let's say let's say that hmm
70 percent of this got stored 70 percent
gets stored of that that is 28 grams and
only 12 grams was oxidized he said oh my
god
only 28 only 12 grams of fat was
oxidized you have the only 840 28 grams
of stored you actually stored less fat
if you're in a negative energy balance
you actually stolen less fat with the
high carb diet than you did with a low
carb diet now I'm not saying that's
exactly what happens I'm saying that if
you're in the same if you were in the
same energy balance in the same amount
of negative energy balance high carb
versus low fat high carb versus low carb
wouldn't make the difference on how much
fat you actually lose or gain it will
make a difference on the rates of fat
oxidation and the rates of fat storage
or the percentage of fat you store from
what you eat because insulin changes but
energy balance is always going to
dictate how much body fat you actually
lose now real quick
let's we've kind of talked about this a
little bit let's say you're in a
negative energy balance what what
happens right well if you're in an
overall negative energy balance where do
all this of whether you're eating high
carb low carb high fat low fat if you're
in a negative energy balance the flux is
going to be out of adipose tissue
because the amount of energy you're
expending is greater than the amount of
energy you are taking in and thus your
tissues are going to require you to
liberate fatty acids from storage in
order to continue to function because
the main goal of the body
you want to keep blood glucose stable
you also want to spare a muscle glycogen
the body's pretty stingy with glycogen
in order to do that what does it use to
spare that well it uses fat okay because
if you are burning more fat if you're
burning liberated fat you're not using
blood glucose you're not using muscle
glycogen as much for things you don't
need it for because muscle glycogen is
something that is a very specific
purpose that are very high intensity
short bursts right see that line
we got run from that line right you
don't want to be out I'm also glycogen
when you go to do that all right that's
why the body's very stingy with it same
token if you're in a caloric surplus
like we talked about last time if you're
in a positive energy balance even though
you may be if you're on a high-fat diet
again you may be burning more fat you're
also storing more fat because you're
taking so much more in okay and so the
flux is going to be into adipose tissue
all right guys I hope this has helped
you understand fat metabolism a little
bit more and how kind of fat fluxes
throughout the body we're going to go a
little bit more in depth in some of the
the coming series if there's some stuff
I'm missing or some stuff you'd like to
see me address ask it in the comment
below also here in a few weeks I have a
seminar coming up in Miami we've sold
out completely the VIP spots but we
still do have standard seminar spots and
I'm going to talk about some of this
stuff that I'm talking about here but in
person you can ask me questions it's
going to be awesome if you're interested
check out the description we'll put a
link below and we'll also put a
clickable link here in the video as well
thanks for watching guys I'll catch you
next time
you
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