Changing Fast Carbs to Slow Carbs for Weight Loss | Jason Fung

Summary

This video script delves into the world of starches, explaining their classification into rapidly digested, slowly digested, and resistant starches. It highlights the importance of the type of starch and its impact on glucose and insulin levels, which are crucial for weight management. The script discusses five types of resistant starch, their sources, and how they can aid in weight loss by influencing satiety hormones. It also covers six factors that can modify carbohydrate digestion and glucose absorption, emphasizing the role of fiber, phenolics, and the processing of starches.

Takeaways

• 🌾 Starch, such as oat, beans, wheat, and rice, is a polysaccharide, meaning it's a long chain of glucose molecules.
• 🔍 Starch is categorized into rapidly digested, slowly digested, and resistant starch, replacing the old complex versus simple carbohydrates classification.
• 🔄 The old classification based on glucose chain length was not useful as it didn't reflect the human physiological response to starch digestion.
• 🌱 Amylopectin (Amal pectin) is more water-soluble and easily degraded by enzymes called amylases, while amylose (amalo) is harder to digest due to its helical structure.
• 🍚 There are three types of amylopectin: A (easily digested, found in wheat), B (intermediate, found in potatoes and bananas), and C (hardest to digest, found in beans).
• 📊 The speed of digestion is crucial for glucose and insulin release, with amalo starches causing less insulin release compared to amylopectin, even with the same amount of carbohydrates.
• 🔑 Six factors influence carbohydrate digestion and glucose rise: the ratio of amylose to amylopectin, particle size, cell wall integrity, co-consumption of fats and proteins, presence of acidic foods, and phenolic compounds.
• 🌀 Resistant starches reach the colon and are broken down by gut bacteria into short-chain fatty acids, which can promote satiety and decrease gastric emptying.
• 🍚 Type 1 resistant starch is trapped within an intact cell wall or protein matrix, making it inaccessible to digestive enzymes.
• 🌾 High amylose starch (Type 2) is found in certain varieties of rice and unripened potatoes and bananas, and is more resistant to digestion.
• 🍲 Type 3 resistant starch is created by cooking and cooling starches, which form a new crystal structure less susceptible to amylase enzymes.
• 🚫 Type 4 resistant starch is chemically modified and not recommended due to its highly processed nature.
• 🥘 Type 5 resistant starch involves the complex of starch and lipid, where fat acts as a barrier to digestion, though it is less studied.

Q & A

What are the two main forms of starches found in the human diet?

The two main forms of starches found in the human diet are Amylose and Amylopectin, with Amylose making up about 70% and Amylopectin about 30%.

What is the difference between rapidly digested starch and resistant starch?

Rapidly digested starch releases glucose within about 20 minutes of eating, while resistant starch is not broken down at all and goes to the colon where it is acted upon by gut microbiome.

Why was the old classification of carbohydrates as complex versus simple not useful?

The old classification was not useful because it was based on the chemical composition of the starch and not on the human physiological response. Many long chains of glucose, considered complex carbohydrates, are rapidly digested and cause a quick spike in glucose, contrary to the expectation.

What are the three types of Amylose and how do they differ in digestibility?

The three types of Amylose are Amylose A, Amylose B, and Amylose C. Amylose A, found in wheat, is the most easily digested. Amylose C, found in beans, is the hardest to digest. Amylose B, found in potatoes and bananas, is intermediate between the two.

How does the structure of Amylopectin affect its digestibility?

Amylopectin has a helical structure which makes it much harder to digest compared to the straight chains of Amylose, leading to a slower rise in glucose and insulin levels.

What are the six major factors that influence the carbohydrate digestion and glucose rise?

The six major factors are the Amylose to Amylopectin ratio, particle size, cell wall integrity, the presence of fats and proteins, the presence of acidic foods, and phenolic compounds.

How does resistant starch contribute to weight loss and glucose sensitivity?

Resistant starch, being undigested, goes to the colon where it is broken down by gut bacteria into short-chain fatty acids. These stimulate hormones like GLP-1 and peptide YY, promoting satiety and reducing gastric emptying, which can influence glucose sensitivity and decrease insulin release.

What is Type 1 resistant starch and how is it formed?

Type 1 resistant starch is the carbohydrate trapped within a physical barrier like an intact cell wall or a protein matrix, which prevents digestive enzymes from accessing it.

What is the process of retrogradation and how does it create Type 3 resistant starch?

Retrogradation is the process where starches form a new crystal structure after being cooked and cooled. This makes the starch more stable and less susceptible to digestion by amylase enzymes, creating Type 3 resistant starch.

Why is chemically modified starch (Type 4) not recommended and what processes are used to create it?

Chemically modified starch is not recommended because it is highly processed and involves chemical treatments like crosslinking, etherification, and esterification, which are generally not considered healthy.

What is Type 5 resistant starch and how does it differ from the other types?

Type 5 resistant starch is a complex of starch and lipid where the fat acts as a physical barrier, preventing the quick breakdown of starch by digestive enzymes. It has not been well-studied and is less understood compared to other types.

Outlines

00:00

🍚 Understanding Starch Types and Digestion

This paragraph delves into the world of starches, explaining the two main forms: Amylose and Amylopectin, which are long chains of glucose arranged differently. Amylose is more water-soluble and easier to digest, while Amylopectin is harder due to its helical structure. The speaker clarifies that starches are categorized into rapidly digested, slowly digested, and resistant starch based on the speed of glucose release, replacing the outdated complex versus simple carbohydrates classification. The paragraph also discusses how the ratio of Amylose to Amylopectin, particle size, cell wall integrity, co-consumption of fats and proteins, and the presence of acidic foods can influence carbohydrate digestion and glucose absorption.

05:00

🌾 Exploring the Impact of Resistant Starch on Weight Loss

The second paragraph focuses on resistant starch, which is not digested in the small intestine but instead reaches the colon where it is fermented by gut bacteria, producing short-chain fatty acids that can influence hormones like GLP-1 and Peptide YY, promoting satiety. The speaker introduces five types of resistant starch, including Type 1 (trapped within a physical barrier), Type 2 (high Amylopectin starch found in certain varieties of rice and unripened potatoes), Type 3 (formed by cooking and cooling starches which undergo retrogradation), Type 4 (chemically modified starch, not recommended), and Type 5 (complex of starch and lipid). The paragraph emphasizes the importance of starch modification and the role of insulin in weight gain.

10:00

🥔 Utilizing Resistant Starch for Healthier Diet Options

In the final paragraph, the discussion continues with practical examples of how resistant starch can be incorporated into one's diet for health benefits. The speaker mentions the benefits of consuming cold cooked rice or potato salad with vinegar, which can significantly reduce the glycemic index and insulin response. The paragraph concludes by emphasizing the importance of understanding the different types of starches and how they can be modified through various means to influence glucose and insulin levels, ultimately affecting weight management.

Keywords

💡Resistant Starch

Resistant Starch refers to a type of dietary fiber that is not digested in the small intestine and instead reaches the large intestine where it is fermented by gut bacteria. In the video, it is discussed as a potential aid for weight loss due to its effect on glucose and insulin levels, which can influence satiety and appetite. The script mentions that resistant starch can be found in various forms and is linked to the production of short-chain fatty acids that promote a feeling of fullness.

💡Polysaccharides

Polysaccharides are complex carbohydrates made up of long chains of sugar molecules, such as glucose. They are the main form of energy storage in plants. In the context of the video, polysaccharides like starches are broken down into glucose, which can affect blood sugar levels and insulin response, playing a significant role in weight management.

💡Amalopectin and Amylopectin

Amalopectin and Amylopectin are two main forms of starch. Amylopectin is more water-soluble and is digested more easily by enzymes, while Amalose is harder to digest due to its helical structure. The video explains that the ratio and type of these starches in food can affect the rate at which glucose is released into the bloodstream, impacting weight loss efforts.

💡Rapidly Digested Starch

Rapidly Digested Starch is a classification of starch that is broken down quickly, releasing glucose within about 20 minutes of consumption. The video script uses this term to illustrate how certain types of carbohydrates can lead to a rapid spike in blood sugar, which is not ideal for weight management or maintaining stable insulin levels.

💡Slowly Digested Starch

Slowly Digested Starch is another classification that refers to starches that take longer than 20 minutes to break down and release glucose. The video emphasizes the importance of this type of starch in managing blood sugar levels more effectively, which can be beneficial for weight loss.

💡Insulin

Insulin is a hormone that regulates blood sugar levels by allowing glucose to enter cells. In the video, it is mentioned that the rate at which starches are digested can affect insulin release, which in turn influences appetite and weight gain. Managing insulin levels through diet is suggested as a strategy for weight management.

💡Particle Size

Particle size refers to the physical dimensions of food particles, which can affect the rate of digestion. The video script explains that larger particles tend to digest slower, while smaller, finely milled particles can be digested more quickly, impacting the speed at which glucose enters the bloodstream.

💡Cell Wall Integrity

Cell Wall Integrity relates to the intactness of the cell walls surrounding carbohydrates. In the video, it is discussed that carbohydrates within intact cell walls are harder to digest, thus slowing glucose absorption. This concept is used to explain why whole grains might be healthier options compared to finely processed grains.

💡Fermented Foods

Fermented foods, such as those containing vinegar, are mentioned in the video as agents that can influence the speed of starch digestion. They do so by affecting the amount of amylase enzymes, which break down carbohydrates, and potentially reducing the glycemic index of a meal.

💡Phenolic Compounds

Phenolic compounds are plant-based antioxidants that can modulate carbohydrate digestion and glucose absorption. The video script suggests that these compounds, found in various plant foods, can inhibit the enzymes that break down carbohydrates, thus slowing glucose absorption and potentially aiding in weight loss.

💡Type 1 Resistant Starch

Type 1 Resistant Starch is a form of starch where the carbohydrate is physically trapped within an intact cell wall or protein matrix, making it inaccessible to digestive enzymes. The video uses examples like whole grains to illustrate how this type of resistant starch can contribute to a feeling of fullness without spiking blood sugar levels.

💡High Amylose Starch

High Amylose Starch, also known as HM (High Amylose) starch, is a genetically modified form of starch with a higher concentration of Amylose. The video script explains that certain varieties of rice and unripened bananas have high Amylose content, which makes them harder to digest and thus can be beneficial for weight loss.

💡Type 3 Resistant Starch

Type 3 Resistant Starch is formed when starches are cooked and then cooled, undergoing a process called retrogradation. The video script discusses how this process creates a new crystal structure that is more resistant to digestion, leading to a slower rise in blood sugar levels, which can be advantageous for weight management.

💡Chemically Modified Starch

Chemically Modified Starch, or Type 4 Resistant Starch, is created through processes like crosslinking, etherization, and esterification. The video script cautions against this type of starch due to its highly processed nature and lack of health benefits, unlike the other types of resistant starch.

💡Starch and Lipid Complex

Starch and Lipid Complex, or Type 5 Resistant Starch, involves fats acting as a physical barrier that separates amylase enzymes from starch, preventing quick breakdown. The video script mentions a study where stir-fried rice with oil had a lower glycemic impact than fried rice without oil, suggesting that the presence of fat can influence starch digestibility.

Highlights

Starch is classified into rapidly digested, slowly digested, and resistant starch, replacing the old complex versus simple carbohydrates classification.

Amal optin and amalo are the two main forms of starch, with different digestibility and impacts on glucose and insulin levels.

Amal optin comes in three types (A, B, and C), each with varying digestibility rates found in different foods.

Amalo starch has a helical structure that is harder to digest, leading to slower glucose and insulin rises.

The speed of digestion is crucial for glucose and insulin release, affecting how different starches impact the body.

Six factors influence carbohydrate digestion speed: starch type, particle size, cell wall integrity, fat and protein co-consumption, acidic foods, and phenolics.

Resistant starches are not digested and reach the colon, where they are broken down by gut microbiome into short-chain fatty acids.

Resistant starch types include physical barriers, high amylose starches, and retrograded starches formed by cooking and cooling.

Type 1 resistant starch is trapped within intact cell walls or protein matrices, making it inaccessible to digestive enzymes.

High amylose maize (HAM) and certain rice varieties have higher amylose content, contributing to type 2 resistant starch.

Type 3 resistant starch is formed when cooked starches are cooled, undergoing retrogradation and becoming less digestible.

Chemically modified starch (type 4) is not recommended due to its highly processed nature.

Type 5 resistant starch involves the complex of starch and lipid, where fat acts as a barrier to digestion.

The presence of fiber and phenolics are key factors in reducing glucose absorption and insulin release.

Eating order and the presence of vinegar can significantly influence the glycemic index and insulin response.

Different types of resistant starch have practical applications for weight management and blood sugar control.

The video emphasizes the importance of understanding starch types and their modifications for health and weight loss.

Transcripts

hi today I'm going to talk about the

five types of resistant starch and how

they might help you to try to lose

weight and it's coming right

[Music]

up starches things like oat and beans

and wheat and rice are called

polysaccharides and that means that

they're long chains of glucose which is

a type of sugar and they come arranged

in two main forms one called Amal optin

which is about 70% in the human diet and

the other type is amalo which is about

30% the starches are usually classified

into three different types rapidly

digested starch which means that the

glucose is released within about 20

minutes of eating then there's slowly

digested starch which is slower than 20

minutes and then resistant starch which

is not broken down at all and this

replaces the old classification of

carbohydrates which was complex versus

simple carbohydrates and the old

classification was based on how long

those chains of glucose were if it was a

simple carbohydrate it was one or two

molecules and it was thought that that

would lead to a very quick rise in

glucose and a complex carbohydrate which

is longer chains like the amalo and Amal

optin were thought to be digested slower

but it turns out not to be true because

many many of these uh long chains that

is complex carbohydrates actually are

rapidly digested and therefore cause a

very quick Spike so that old

classification wasn't useful because

it's really based on a chemical

composition of the starge and is not

based on the human physiologic response

which is why we use these different

terms tin has a different structure than

amalo so Amal optin is more water

soluble and makes it easier to be

degraded by enzymes called amasis the uh

Amal optin comes in three different

types Amal optin a which is found in

wheat and is the most easily digested

Amal optin C is the hardest to digest

and those are found in things like beans

Amal opcin B which is found in potatoes

and bananas is sort of intermediate

between the two amalo with its helical

structure which is straight is much

harder to digest and therefore leads to

a much slower rise in the glucose and

the insulin and in this study for

example you see that this is true in

both normal um people and also

hyperinsulinemic people if they eat more

amalo compared to Amal optin the amount

of insulin that is released is much less

even though the amount of carbohydrate

is the same and as we've seen the speed

of the digestion is critically important

to how much gluc glucose and Insulin

released there's actually six major

forms of uh ways that can be influence

the uh the carbohydrate from uh what you

eat to how quick the glucose Rises so

the first is as we've discussed the

amalo uh pectin to amose ratio and how

much resistance starch there is uh

second is the particle size that is if

you have much larger particles they tend

to be digested much slower if you have

something which is grind up and very

small it can be digested very quickly so

uh for example if you

have uh deel cut oats versus very finely

milled instant oats there's a difference

because the particle size is smaller the

third is a cell wall Integrity so if you

have the uh carbohydrate within an

intact cell wall it can't be digested

that's why fiber is often considered an

indigestible carbohydrate if you break

down that cell wall by taking wheat for

example and grinding it very very fine

into a dust it gives it uh a lot of

opportunity for the amasis those enzymes

in our body to break it down leading to

an extremely rapid rise in blood glucose

compared this finely machine grade uh

industrially processed wheat to say

stone ground wheat and you find that the

the cell wall Integrity is more intact

and therefore a slower rise number four

is if you eat the fats and proteins

along with the carbohydrates and I did a

whole YouTube video uh describing why

food order matters and why eating the

carbs last might be more beneficial uh

number five is the presence of acidic

Foods things such as

vinegar and other uh fermented foods can

influence the speed at which is digested

by influencing the amount of amasis and

again I did a whole YouTube video on

that if you want to check that out and

number six is something called phenolic

which we may address in another video

when phenolics are antioxidants they're

phytochemicals so they're found uh from

plants and they're things called like

phenolic acid and flavonoids and lignins

and they modulate carbohydrate digestion

and glucose absorption by also

inhibiting inhibiting these Amal phes

that break down the carbohydrate and um

they can also influence the intestinal

glucose transporter so by by inhibiting

the amalay is it makes the absorption

much slower and certain Studies have

shown that uh perhaps the most important

factors could be the amount of uh fiber

and also the uh presence of uh phenolics

so what about resistant starch because

resistant starch is not digested at all

and by taking more resistant starch you

might be able to influence that how much

carbohydrate you can take and reduce it

and there's five different types of

resistant

starch because they don't get digested

at all it goes to the colon and the

carbohydrate then gets acted on by the

uh gut microbiome so those bacteria that

are in the colon start to break it down

into things such as short chain fatty

acid or SF s

CFA and that is important because that

has other influences it stimulates for

example glp1 which is a hormone which uh

May promote satiety and decrease gastric

emptying and also peptide YY which

promotes satiety so this fiber even

though there is no um absorption the

carbohydrate goes straight through us

doesn't going absorb can still make us

feel more full and make us want to stop

eating and this will have an influence

in terms of glucose sensitivity and

decreasing the amount of insulin

released the the the first type of

resistant starch is type one resistant

starch which is that the carbohydrate is

trapped within a physical barrier um or

a uh and that usually is an intact cell

wall because it is contained with in

that cell wall or perhaps a protein

matrix therefore the digestive enzyme s

like the amales can't get add it because

they're physically blocked the fiber is

the most classic example of that where

the carbohydrate is trapped within the

intact cell wall and therefore you can't

do it you can release the carbohydrate

by industrial processes such as grinding

but also Milling sometimes chewing can

also uh release that um so if you uh

look at those examples like uh machine

ground Flow versus uh stone ground flour

or Steel oats versus instant oats

there's clearly a difference when it

comes to the effect on our bodies even

though the carbohydrate is the same the

second type of starch is called high

amalo starch and because the amalo is

digested slower you can modify mostly

genetically the uh corn and sometimes

wheat to have a much higher amalo

concentration it's called hm or high

amalo maze um that's not very common

however uh the other way to look at it

is to look at the different varieties

and here they've done some um some

studies on rice and certain types of

rice are much higher in amalo than

others the highest variety rice is

basmati rice as well as Jasmine and

they're about 30% so on par with wheat

but the uh sticky rice or glutenous rice

has almost 0% amalo it's mostly almost

all amalo pectin and in between is a

short grain rice which is about 10 to

20% the other thing that is very high in

amalo are unripened potatoes unripened

bananas Maybe Baby potatoes as well um

there the starches are very uh difficult

to digest the third type of resistant

starch or type three resistant starch is

uh cooking and then cooling starches and

this is very interesting because heating

the starches actually causes

gelatinization which is turning it into

a more liquid form so cold rice for

example is very crunchy because it's

it's a crystal and then as it's more

liquid it's smoother and softer and much

easier to eat as that Rice cools uh it

forms a new crystal structure in a

process called retrogradation so you may

also see that term retrograded starch

and this makes the starch more stable

and again less susceptible to amalay and

again if you uh the amalay can't break

down the starch it can't get absorbed so

therefore the rise in glucose is much

slower than if you had just regular rice

so cooked and then cooled rice uh can be

compared in this study for example uh

they they found that there was a small

but significant uh decrease in the rise

in glucose when you had uh type 3

resistant starch potatoes on the other

hand if you were to cook them cool them

and then reheat them

uh most of that starch just goes back

into its normal structure so it doesn't

have any effect but the good thing about

potatoes is that you can eat them cold

so if you cook them and then cool them

and then eat them cold such as with

potato salad for example then again you

can take advantage of this resistant

starch so uh one study for example

showed that if you ate uh potato salad

where you also had some vinegar dressing

which may play an effect you could

actually reduce the gemic index by a

whopping 41% compared to regular

potatoes and uh reduce the insulin by

31% so that's a very interesting way to

modify uh the starch which is called

retrogradation or type 3 resistance

starch type four is a chemically

modified starch and this is not

recommended because it's highly

processed what they do is they use uh

chemicals to do things like crosslinking

etherization esterification and just by

hearing the name you know that that's

probably not something you want to eat

and type five is the complex of the

starch and lipid where the fat acts as a

physical barrier separating uh the

amalay and the starch and therefore

preventing the quick breakdown so uh

this has not been studied well so

there's not a lot of evidence however

there is a small study for example where

they looked at stir fried rice and oil

versus fried rice without oil and the

oil acts as a physical barrier to make

it uh easier to uh have so those are the

different types of resistant starch

there's five different types and it's

very important that all starches are not

the same there's those six different

ways that you can modify it so again

it's not the carbohydrate necessarily

because all of these have the same

amount of carbohydrate but what you what

what you do to the carbohydrate whether

you change it into a more resistant form

or you add things like proteins or fats

or vinegars or you uh keep it in a more

whole form uh that that can really

influence the amount of uh the how

quickly the the uh glucose Rises and

therefore the amount of insulin produced

and it's that hormone insulin which is

driving weight gain I hope you've

learned something I'll see you next week