Have you ever been told that sugar is bad and that you should stop eating it?
Probably.
But then you may have wondered why is it bad?
And if it is, how bad are we talking here?
Like a little bad and I can still eat my cookies or a lot of bad and I should stop eating it
immediately.
Well, in today's video, we're going to answer these questions as well as talk about how
the body processes sugar, what sugar actually is, and even talk about how exercise can change
how we utilize and process the sugar.
This is going to be full of all sorts of sugary anatomical awesomeness.
So, let's do this!
[Intro]
So first, what do we even mean when we use the word "Sugar"?
Most of us are referring to table sugar and this can sometimes be associated with some
negative connotations.
Maybe you've heard things like sugar is bad for you.
It causes weight gain.
It's associated with diabetes.
It can cause inflammation and the list goes on and on, but are these accurate or even
fair assessments of sugar and could there ever be potential situations where sugar might
be beneficial?
Because in biology, the term sugar is used to refer to certain types of carbohydrates
and what you might find interesting is that as we talk sugar, we're going to find that
the same types of carbohydrates that are found in table sugar are the same carbohydrates
that are found in fruits, vegetables and other whole food sources that we typically consider
as good for us.
So, we definitely need to go a little bit deeper into this sugar discussion and let's
start with the term "carbohydrate".
Carbohydrates are compounds that are made of carbon hydrogen and oxygen and they include
things like sugars, starches, and even cellulose.
Now, cellulose, we're not talk a lot about because this is something our body can't break
down and absorb and it is one of the contributors to the fiber in your diet so it helps push
things along in your large intestines so that you can have epically amazing bowel movements,
but sugars and starches, we can definitely break down and absorb into the bloodstream
through the small intestine and we typically use these as energy sources.
And so again, sugars and starches fall under this umbrella of carbohydrates but what are
some of the differences?
Now, the term is referring to simple carbohydrates.
You may have heard of the phrase "simple sugars" before.
Now, these are smaller carbohydrate molecules which includes things that are called disaccharides
and monosaccharides.
Saccharide just means sugar, "Di" means two, "Mono: means one and so, a disaccharide is
made up of two monosaccharides.
Now, even though we're using some of these jargony biology terms, you have likely heard
of disaccharides and monosaccharides that are found in the foods you eat.
For example, lactose is the disaccharide found in milk products and of course, sucrose is
the disaccharide that makes up table sugar and since we're really kind of focusing in
on this table sugar, this table sugar, AKA, sucrose is made up of one monosaccharide called
glucose bonded to another monosaccharide called fructose.
So glucose plus fructose equals sucrose which is table sugar.
So, if we kind of take a step back - imagine yourself holding a spoonful of sugar and that
spoonful of sugar is made up of multiple, multiple molecules of sucrose and therefore
the building blocks of glucose and fructose and you're about to eat it.
But of course you're an inquisitive mind about biology, anatomy and physiology and you're
thinking to yourself "What is it about this table sugar - and therefore the fructose and
glucose that's found in this that makes it worse than the glucose or fructose that I
find just in the fruits and vegetables and other food sources?
Well, to answer that.
I think we need to talk a little bit about the starches.
Starches are complex carbohydrates which are polysaccharides, and the starches that humans
ingest the most are amylose and amylopectin and these are multiple glucose molecules strung
together or bonded together or you could think of them as these long chains of glucose, hence
they are referred to as polysaccharides.
Now, we can definitely compare and contrast these to the disaccharides or the table sugar
as we can see yes, they both do contain glucose but there's a huge difference in the size
of say table sugar versus the size of the molecules that make up the starches, and this
is where you start to see some discuss a negative potential effect of the table sugar and that
has to do with how it's broken down and absorbed into the body when you compare it to the starches.
So, we need to talk about what happens when you put the table sugar in your mouth versus
what happens when you put the starch in your mouth.
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So, back to the ingesting of sugars and starches and this discussion around how bad is sugar.
So, once we place the sugar and starches into our mouths, what we refer to as the oral cavity
in anatomy, this is where the process of digestion begins - through chewing and through the secretion
of saliva which contains certain enzymes to help start this digestive process.
We then move this down the esophagus and into the stomach where the sugars and starches
will mix with the acid through the smooth muscle contractions of the stomach and this
mixture will eventually make it to the first part of the small intestine called the duodenum.
Now, the duodenum contains specific enzymes that can break down specific types of carbohydrates
- for example sucrose will break down sucrose, the table sugar into the individual glucose
and fructose molecules that we talked about earlier.
Amylase is a specific enzyme to breaking down amylose and what's important to understand
is that our bodies can only absorb the monosaccharides, meaning the individual glucose and fructose
molecules.
So, you can see that this breakdown and digestive process is important for the absorption.
And as those glucose and fructose molecules move further down the small intestine as they've
been freed through the digestive process, they'll move into the and duodenum the ilium,
second and third part of the small intestine, and then be absorbed through the wall and
into the bloodstream.
And once those glucose and fructose molecules are in the bloodstream, the first place that
they will go is to the liver.
Now, the liver does a lot of different but one of the first things that we'll do is convert
those fructose molecules into glucose molecules.
So, we don't have all this fructose circulating throughout the body and when you think about
that from a clinical setting, when we measure say like blood sugar levels, we're measuring
blood glucose levels as glucose is this primary monosaccharide that's circulating throughout
our body.
But I did graze over something kind of quickly there, and that was the breakdown and the
absorption rate of say like a sugar versus the breakdown an absorption rate of a starch.
And remember, we mentioned that sugars are relatively small carbohydrate molecules - the
disaccharides, especially when we compare them to the complex carbohydrates, polysaccharides
and because of this difference, the sugars, the disaccharides, tend to be broken down
and absorbed much more quickly.
So, blood sugar levels will rise more rapidly but they'll also taper off or go down more
rapidly as compared to say like a complex carbohydrate where that breakdown or that
digestion is more slow and so, the blood sugar levels tend to rise more slowly but they also
tend to be sustained for a longer period of time.
And this is one of the negative things you can think of or that sometimes mentioned about
sugar is that the blood sugar levels could spike but then also kind of crash down.
Now, you can combat that in some situations.
If you only ate a simple sugar, you'd kind of deal with that spike and crash but if you
paired that simple sugar, say with complex sugar or complex carbohydrate, yes, the blood
sugar levels would increase relatively rapidly but then you get that sustained blood sugar
level because you'd have that complex carbohydrate following behind.
Now, there are certain situations where I want a simple sugar or a sugar to get in there
and raise the blood sugar levels quickly.
For example, say like in a clinical setting, I had a patient that was hypoglycemic.
I don't want to wait for a complex carbohydrate, I want to get a simple sugar in there to raise
the blood sugar levels up to get them out of that hypoglycemic state.
Maybe I'm a marathon runner and a halfway through the marathon, my glucose levels are
getting low and I need to get an energy boost of glucose into my bloodstream as quickly
as possible.
Yes, the ideal situation is to have a balanced intake of carbohydrates or blood glucose levels
but as you can see, there are certain situations where it can be appropriate to get that glucose
into the bloodstream as quickly as possible.
And one thing I do want to mention is that in the clinical setting, if we have to get
somebody's blood sugar levels up or during a marathon, it's not like giving people like
spoonfuls of table sugar - there are certain mixtures or products that are made up of simple
sugars or simple carbohydrates to get this done but if you are in a pinch, a sugary drink
or a sugary juice often will have the same effect and we have to go back to this idea
that I mentioned or alluded to earlier, the glucose molecule in table sugar is the exact
same structure in form as the glucose molecule that came from some fruit, vegetable, or other
whole food source.
It's not like the glucose molecule from the sugar is labeled as poison.
It's not like your body has this glucose segregating police force that says, "You, glucose molecule
that came from the sugar, you are banished for the fat cell.
But you, glucose molecule that came from the whole grain food, you can go into the muscle
cell and you, the glucose molecule that came from the kale, you can go into the nerve cell."
No, your body doesn't care or the difference between where the glucose came from.
Glucose is glucose.
Now, even though I said "glucose is glucose" and that our body doesn't differentiate between
the sources from where the glucose comes from, there are still some important considerations
we have to have when it comes to sugar.
For example, sugar is often referred to as "Empty calories".
Meaning, that glucose and fructose is essentially all we get in the form of calories and energy
from that sugar as opposed to getting that glucose and fructose from whole food sources.
In that case, that glucose and fructose is often going to be associated with other benefits
with things like vitamins, fiber, and other nutrients that can help bolster health and
wellness.
And building further off of this idea of empty calories - if we had to pick the most negative
thing when it comes to sugar, it's probably this - we can eat a ton of it without actually
feeling that full and when you think about it from the perspective of say like early
human ancestors or hunter gathers, did they get carbohydrates and some simple sugars through
fruits and vegetables?
Yes, of course, but were they also creating these factories where they were developing
refined table sugar to also add to the foods they were already eating?
No, but we do.
Think about maybe the last time you went to a restaurant.
Maybe instead of ordering a water, you ordered a soda and maybe you got two to three refills
and that extra sugar that was in that soda was ingested and probably didn't make you
feel any more full than if you just had two to three glasses of water instead.
Also, adding that sugar to foods that we already eat.
Again, probably doesn't increase how full we feel but increases the amount of carbohydrates
and sugars and therefore, calories that we ingest on a day-to-day basis.
Again, depending on how much sugar that you ingest and so, this whole idea again is we've
changed the ratio and therefore, the total amount of carbohydrates and sugars that we
ingest.
The sugar in and of itself is not evil.
It's the amount that we're getting easily included in our daily diet.
So, another thing that I think will be helpful is for us to understand what happens is the
glucose circulates throughout the body and what happens is there's too much.
Now, we already know that the glucose will first go to the liver and any fructose that's
in there will just get converted to glucose anyway but the liver will also start to store
the glucose in its storage form which is called glycogen and the liver can store about 100
grams of glycogen and the rest of the glucose that isn't stored in the liver will circulate
out the body and yes, insulin is going to be released by the pancreas in response to
these increasing blood sugar levels and we're going to do a whole video series on insulin
and diabetes.
So, for now, just know that insulin essentially tells the majority of the cells in your body
to take the glucose from the bloodstream and into themselves.
Therefore, lowering blood glucose or blood sugar levels.
And if we take a look at skeletal muscle in particular, that glucose that gets pulled
into the skeletal muscle tissue will also get stored as glycogen and the skeletal muscles
throughout your body could store about 400 to 500 grams of glycogen depending on who
you are.
So, kind of think of the liver and the skeletal muscle tissue is little gas tanks for glucose
and glycogen.
But, what happens when we've completely filled up the liver, completely filled up the skeletal
muscle tissue and there's still more glucose in the bloodstream?
That's when we start seeing the glucose getting converted to fat and getting stored in the
adipose tissue and that's where we can start to run into problems by really increasing
our glucose or our sugar intake beyond the capacity of say like our liver and our skeletal
muscle tissue.
So, hopefully that gives you a different perspective or a better understanding of how sugar can
be bad.
So, consistently ingesting too much of it and having increased blood glucose levels
and that excess blood glucose getting stored as fat and increasing weight over time and
the associations of increased adipose with things like diabetes, cardiovascular disease,
and other conditions but finally, how does exercise influence or even change how we process
sugar or glucose?
Moderate to intense activity causes the skeletal muscles to preferentially shift their source
of energy to burning more carbohydrates more so than fats.
Also, as someone increases their activity or consistently exercises, their ability to
store glycogen in their skeletal muscles increases.
So, think as your skeletal muscle gas tank for glycogen getting bigger so you can store
more glycogen and if you compared that to a sedentary or an inactive person with that
of an active person, those who are inactive, you'd see that their resting glycogen stores
are about 20 to 30% less than the active person.
So, in theory, someone who's consistently active could eat more carbohydrates not only
because they're just burning more calories on a day-to-day basis but also because they
have the ability to store more of it in their skeletal muscles before it'll start getting
converted to fat.
Exercise also sensitizes muscles to insulin especially directly after exercise and this
is kind of the opposite of what happens during type 2 diabetes.
Generally, we say with type 2 diabetes that the majority of cells throughout the body
become insensitive to insulin but exercise has this sensitizing effect especially with
the skeletal muscles.
And speaking of insulin, something that's really cool with exercise is that an exercising
muscle doesn't actually need insulin to bring in the glucose like a resting muscle does.
So, say you're running a marathon or exercising and you ingest like a simple sugar or a carbohydrate
to replenish your carbohydrate stores, those contracting muscles can bring in the glucose
without the need for insulin.
So obviously you can see there are some amazing benefits to exercise through how it helps
us to process and utilize those sugars or that glucose.
And again, hopefully all of this help to just clarify how and when sugar can be bad and
of course, if you made me pick between the two extremes - say I had someone that didn't
eat any processed sugar and only got their carbohydrates from whole food sources versus
someone who ate a ton of sugar.
Obviously, we're going to pick the situation where we get our carbohydrates only from the
whole food sources but most of us don't live on those two extremes and as long as the majority
of your carbohydrates come from whole food sources and you have this balanced ratio of
carbohydrates to lipids to proteins, you're likely going to be just fine with indulging
into your favorite sugary treat every so often.
And remember, one of the best times to that is directly after exercise when those skeletal
muscles are sensitized to bring in that glucose to replenish the glycogen stores and FYI,
it's also a good time to add protein to that because your skeletal muscles are primed to
also bring in those amino acids or those proteins to help the rebuilding process.
And as always, thank you for watching everyone.
We really do appreciate everyone's support in making this channel possible.
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