Is The Keto Diet Healthy? (Saturated Fats) | Jason Fung

Summary

The video script challenges the conventional belief that a high intake of saturated fat, as seen in the ketogenic diet, leads to heart disease. It reviews recent evidence, including a state-of-the-art article from the American College of Cardiology, suggesting that natural saturated fats from whole foods may not increase the risk of heart disease, diabetes, or stroke. Instead, it posits that dietary carbohydrates, through de novo lipogenesis, could be more detrimental. The script also highlights historical dietary guidelines, the French paradox, and large-scale studies that indicate a reevaluation of saturated fat's role in heart health.

Takeaways

• 🫀 The keto diet, which includes high levels of total and saturated fat, is not unhealthy and does not clog arteries or cause heart disease.
• 📚 Recent scientific evidence shows that saturated fat does not cause heart disease, contrary to what was believed since the 1960s.
• 🔬 A state-of-the-art review by top cardiologists in the Journal of the American College of Cardiology concluded that there is no benefit in reducing saturated fat intake.
• 🥩 Whole foods like full-fat dairy, red meat, and dark chocolate, which contain saturated fats, do not increase the risk of heart disease, diabetes, or stroke.
• 🍞 Dietary recommendations should focus on whole foods rather than specific nutrients, as the overall food matrix is more important for health.
• 🇺🇸 The 1977 dietary guidelines recommending low fat intake were based on weak evidence and cherry-picked data.
• 🥄 Replacing saturated fats with unsaturated fats or vegetable oils, as was recommended in the past, led to the consumption of trans fats, which are harmful to heart health.
• 🍫 Studies have shown that there is no correlation between total fat intake and the risk of heart disease, and in some cases, higher fat intake is protective.
• 🧀 Full-fat dairy has been linked to a lower risk of diabetes and does not increase the risk of heart disease.
• 🫀 A high carbohydrate intake is more strongly associated with higher levels of saturated fat in the blood and an increased risk of heart disease than dietary fat intake.

Q & A

Is the keto diet considered unhealthy due to its high fat content?

The script suggests that the keto diet, which is high in total fat and saturated fat, is not necessarily unhealthy. Recent scientific evidence and cardiologists' consensus indicate that saturated fat does not cause heart disease, and people who consume more fat may actually be protected against stroke.

What was the conclusion of the review published in the Journal of the American College of Cardiology in August 2020?

The review concluded that reducing saturated fat intake does not have beneficial effects on heart disease. Instead, it found that consuming more fat could be protective against stroke. The top cardiologists recommended making dietary recommendations based on whole foods rather than specific nutrients.

What does the script say about the sources of most saturated fat in our diets?

Most saturated fat comes from whole fat dairy, red meat, and dark chocolate, which are complex food matrices. The script emphasizes that these natural fats do not increase the risk of heart disease, diabetes, or stroke.

What was the initial recommendation in the 1977 U.S. dietary guidelines?

The 1977 U.S. dietary guidelines recommended avoiding too much fat, saturated fat, and cholesterol. However, the script points out that this advice was based on weak evidence and a few observations from an influential researcher.

Why did the low-fat diet become popular, and what was its intended health benefit?

The low-fat diet became popular because it was believed to reduce heart disease by lowering LDL cholesterol levels. However, newer research shows that it's not as simple as that, and the diet may not necessarily lead to a decrease in heart disease risk.

How does the body produce saturated fat in the blood, and what dietary factors are associated with it?

The body produces saturated fat in the blood through a process called de novo lipogenesis, where excess carbohydrates are turned into fats for storage by the liver. The script indicates that the amount of saturated fat in the blood is more related to carbohydrate intake than dietary saturated fat.

What is the 'French Paradox' mentioned in the script, and how does it relate to saturated fat consumption?

The 'French Paradox' refers to the observation that despite consuming a diet high in saturated fat, such as whole fat dairy, the French had less heart disease than other countries. The script suggests that the saturated fat in natural foods does not cause heart disease, thus explaining the paradox.

What did the largest epidemiologic study published in The Lancet in 2017 find regarding saturated fat and heart disease?

The study found that as saturated fat intake increased, the risk of heart disease tended to decrease. It also suggested that consuming a high percentage of carbohydrates in the diet might increase the risk of heart disease.

What is the script's stance on the consumption of whole fat dairy and its relation to diabetes?

The script suggests that contrary to previous recommendations to consume low-fat dairy, whole fat dairy does not lead to an increased risk of heart disease and could protect against diabetes, which is a risk factor for heart disease.

Why have some physicians started to favor the ketogenic diet?

Some physicians favor the ketogenic diet because it includes natural fats and saturated fats, which recent evidence suggests may not lead to heart disease and could be protective against stroke. Additionally, it has been linked to a reduced risk of diabetes.

Outlines

00:00

🧠 Reevaluating the Ketogenic Diet's Impact on Heart Health

This paragraph delves into the controversial topic of the ketogenic diet and its emphasis on high-fat consumption, specifically saturated fats. Historically, saturated fats have been considered a risk factor for heart disease, but recent evidence suggests otherwise. The paragraph reviews a state-of-the-art article from the American College of Cardiology, which concludes that reducing saturated fat intake does not lower the risk of heart disease. Instead, it points out that natural fats from whole foods like dairy, red meat, and dark chocolate do not increase the risk of heart disease, diabetes, or stroke. The emphasis shifts from avoiding specific nutrients to considering the whole food context, challenging the 1977 dietary guidelines that advised against high-fat consumption.

05:02

🍰 The Misconception of Saturated Fat and Heart Disease

This paragraph explores the relationship between saturated fat in the diet and its levels in the blood, highlighting that blood saturated fat levels are more closely related to carbohydrate intake through a process called de novo lipogenesis. The low-fat diet trend, once believed to reduce heart disease by lowering LDL cholesterol, is now seen in a new light as research shows no correlation between dietary saturated fat and blood saturated fat levels. The paragraph also discusses the complexity of food components and how the health effects of fats cannot be isolated from the whole food matrix. It reflects on past dietary recommendations and the unintended consequences of promoting low-fat diets, such as the increased consumption of trans fats, which are now known to be harmful to heart health.

10:02

🥐 The Protective Role of Saturated Fat in Heart Health

The final paragraph presents evidence that challenges the conventional wisdom on saturated fats, suggesting that they may actually be protective against heart disease and stroke. It discusses various studies, including a large epidemiological study that found no correlation between heart disease risk and total fat or saturated fat intake. Instead, it indicates that a diet high in carbohydrates may increase the risk of heart disease. The paragraph also touches on the 'French Paradox,' where high consumption of whole fat dairy in France did not lead to increased heart disease rates. The conclusion drawn from over 50 years of research is that natural saturated fats, as recommended in diets like the ketogenic diet, are not harmful and could potentially offer protective benefits against heart disease and stroke.

Keywords

💡Keto diet

The keto diet, or ketogenic diet, is a high-fat, adequate-protein, low-carbohydrate diet that has been promoted for weight loss and other health benefits. In the video, it is discussed as a diet that includes plenty of total fat and saturated fat, which was traditionally thought to be harmful. However, recent evidence suggests that this diet may not cause heart disease as previously believed.

💡Saturated fat

Saturated fat is a type of fat found primarily in foods like full-fat dairy, red meat, and dark chocolate. It has been a subject of controversy due to its association with heart disease. The video script challenges the traditional view that saturated fat is detrimental to health, citing recent research that shows no increased risk of heart disease, diabetes, or stroke from its consumption.

💡Heart disease

Heart disease, also known as cardiovascular disease, is the leading cause of death globally. In the video, it is discussed in the context of dietary fats and their relation to heart health. The script reviews evidence that suggests saturated fat does not cause heart disease, contrary to previous beliefs.

💡De novo lipogenesis

De novo lipogenesis is a metabolic process where the liver converts excess carbohydrates into fatty acids for storage. The video explains that the amount of saturated fat in the blood is more related to carbohydrate intake through this process than to dietary fat intake, challenging the notion that dietary saturated fat directly leads to heart disease.

💡LDL cholesterol

LDL cholesterol, or 'bad' cholesterol, is a type of lipoprotein that can contribute to plaque buildup in the arteries, potentially leading to heart disease. The video mentions that lower-fat diets may reduce larger LDL particles, which are not thought to cause heart disease, indicating that the relationship between cholesterol and heart disease is more complex than previously thought.

💡Diabetes

Diabetes is a chronic condition characterized by high blood sugar levels, often due to insulin resistance or a lack of insulin production. The video script suggests that diabetes is a significant risk factor for heart disease and that dietary saturated fat is not related to blood saturated fat levels, which are more closely tied to carbohydrate intake.

💡Total fat

Total fat refers to the overall amount of fat in the diet, including both saturated and unsaturated fats. The video argues that the total amount of fat consumed does not correlate with the risk of heart disease, based on extensive reviews of the literature.

💡Carbohydrates

Carbohydrates are a macronutrient found in foods like grains, fruits, and vegetables. The video suggests that consuming a high percentage of carbohydrates in the diet may increase the risk of heart disease, whereas higher fat intake, as in the keto diet, may not.

💡French paradox

The French paradox refers to the observation that despite having a high intake of saturated fats, particularly from whole fat dairy products, the French have a lower incidence of heart disease compared to other countries. The video uses this as an example to support the argument that saturated fat in natural foods does not cause heart disease.

💡Trans fats

Trans fats are a type of unsaturated fat that is often artificially created through hydrogenation of vegetable oils. The video discusses the historical shift towards consuming margarine as a replacement for butter, which led to increased intake of trans fats, now known to be harmful to heart health.

💡Dietary guidelines

Dietary guidelines are recommendations for healthy eating patterns. The video mentions the 1977 U.S. dietary guidelines that advised against the consumption of saturated fat and cholesterol, which were based on limited evidence and have since been challenged by more recent research.

Highlights

The keto diet, which recommends high intake of total and saturated fats, is reviewed for its health implications.

Recent evidence suggests that saturated fat does not cause heart disease, contrary to previous beliefs.

Cardiologists agree that the ketogenic diet's high-fat intake may not be harmful and could be protective against stroke.

A state-of-the-art review published in the Journal of the American College of Cardiology in August 2020 challenges the traditional advice on saturated fat.

Studies over the last 50 years indicate no increased risk of heart disease, diabetes, or stroke from natural saturated fats.

Recommendations should be based on whole foods rather than specific nutrients, according to top heart specialists.

Saturated fats from whole fat dairy, red meat, and dark chocolate are not associated with increased heart disease risk.

The 1977 U.S. dietary guidelines, which advised against saturated fat, were based on limited and potentially cherry-picked data.

De novo lipogenesis, the process of turning excess carbs into saturated fats in the liver, is more related to blood saturated fat levels than dietary fat intake.

Low-fat diets may reduce larger LDL particles not associated with heart disease, while increasing dietary saturated fat may lower blood saturated fat levels.

High levels of palmitoleic acid, a saturated fat, are associated with increased risk of heart disease and stroke.

The interaction of naturally occurring components in foods and unhealthy components induced by processing is crucial for understanding dietary impact.

The shift from butter to margarine in the 1950s due to the belief in heart health benefits of vegetable oils led to increased consumption of harmful trans fats.

Studies from the 1990s and 2000s showed no correlation between total fat or saturated fat intake and heart disease risk.

Consuming more saturated fat was found to be protective against heart disease and stroke in a study of 58,000 people.

The 'French Paradox', where high saturated fat intake did not lead to increased heart disease, challenges the notion that saturated fat is harmful.

The 2017 Landsat study of 135,000 people across 18 countries found no link between heart disease and total or saturated fat intake, but a higher risk with carbohydrate intake.

Whole fat dairy consumption has been linked to a reduced risk of diabetes, which in turn lowers the risk of heart disease.

The ketogenic diet, which includes natural saturated fats, is not associated with unhealthy consequences and may be beneficial for weight loss and heart health.

Transcripts

is the keto diet unhealthy

it recommends eating plenty of total fat

and saturated fat

and isn't that going to clog up your

arteries causing heart attacks

and strokes we're going to review the

latest scientific

evidence as reviewed by the top heart

doctors

[Music]

should you eat saturated fat since the

1960s

doctors have been saying that we should

avoid this to prevent heart disease

but i'm going to review the surprising

results

of the recent evidence that shows that

saturated fat

does not actually cause heart disease

one of the big

trends over the last few years is the

ketogenic diet

that has said you don't have to worry

that eating too much

saturated fat and total fat might cause

heart disease

and surprisingly the cardiologists

agree i'm going to review this article

which was published in the journal of

the american college of cardiology

in august of 2020. it's a

state-of-the-art review which means that

all the top cardiologists the top heart

specialists got together

to discuss should we place limits on how

much saturated fat

we eat and the surprising conclusion

they came to

is this this is their abstract which

says

that many years of studies

have shown that there's actually no

beneficial effects of reducing saturated

fat

on heart disease instead they found that

people

who ate more fat tended to be protected

against stroke this illustration from

this paper

shows that the previous advice was

to limit how much saturated fat you ate

but when they look at all the studies

that have been done over the last 50

years

that you really have to look not just

at the saturated fat in the food but

the whole food all together to determine

whether or not

it's healthy or not most saturated fat

comes from whole fat dairy from red meat

and from dark chocolate

which are complex food matrices that

tend to have a lot of saturated fat

and when you study these foods these

natural fats

it's clear that there's no increased

risk of heart disease

diabetes or stroke so what these

top heart specialists are calling for in

this state of the art review

is that we should make recommendations

not

on specific nutrients but we should base

them

on foods we shouldn't be avoiding

fat because we don't eat fat we eat

foods we eat

dairy we eat meats we eat breads these

are

foods you have to look at the whole food

in context

and when you look at those there's no

reason to avoid

full fat dairy red meat or dark

chocolate

and that's their conclusion after coming

together and discussing it

and we'll go through the evidence why

let's go back in time and see

how we got to this point in 1977

the american government released a

document the dietary guidelines

and in it they specifically recommended

to avoid eating too much fat

too much saturated fat and too much

cholesterol

but the evidence to support this

statement was not very strong

it was based on just a few observations

from an influential researcher this was

a seven-country study

and in it it shows the association

between countries that ate a lot of

saturated fat and their rate of heart

disease

but it wasn't quite true because the

data was

cherry picked when you looked at all the

countries that had data available

the correlation was very weak but

nevertheless

the american government felt that they

had to make some kind of recommendation

so they hastily made that recommendation

to avoid

eating too much fat and too much dietary

fat

and this led to the change

in habits from eating for example animal

fats which are high in saturated fats

and things such as butter and instead we

were recommended

to eat lots of margarine as a

replacement which was made

from unsaturated fats or vegetable oils

it's also important to distinguish

between

the saturated fat in our diets

and the amount of saturated fatty acids

in our blood

because when we look at the science we

see that the amount of saturated fat in

our blood

is more related to the amount of

carbohydrate that we take

through the process of de novo

lipogenesis

de novo lipogenesis is where the body

takes excess carbohydrates and the liver

will turn that into fats for storage and

these tend to be saturated fats

in the blood all of this that i'm going

over

in this video can also be found in that

article so you can have a look at it if

you're interested for more details the

reason the low-fat diet was

thought to reduce heart disease is

because it could lower

the ldl cholesterol and

the ldl cholesterol was associated with

the rate of heart disease

but newer research has shown that it's

not quite that simple

because these lower fat diets tend to

reduce

the larger ldl particles which are not

thought to cause

heart disease on the flip side

we know that things such as diabetes and

other metabolic diseases

contribute hugely to the risk of heart

disease

and the amount of dietary saturated fat

is actually not related to the level of

blood saturated fat because

in fact it tracks much more closer to

the amount of carbohydrates we take in

through that process of de novo

lipogenesis

and therefore higher dietary fat

intake is going to be associated with a

lower saturated fat in the blood whereas

increased carbohydrates in the diet are

going to be

increasing the amount of saturated fat

in the blood exactly the opposite

of what you would think the high

levels of palmitoleic acid a type of

saturated

fat in fact is associated with

a 67 increased risk of heart disease

and a 52 increased risk of stroke

the other thing that became clear over

the last 50 years of research

is that a food is more than just

the macronutrients it contains the carbs

the proteins and the fats because there

are differences

between fats and different the types of

fats that are in it

and it's an interaction between the

naturally occurring components

and the unhealthy components which are

induced by

processing this is best illustrated

in the whole trans fat debacle

in the 1950s vegetable oils were

recognized to lower our serum

cholesterol and therefore thought

to be heart healthy this led to a huge

movement

away from butter and we are encouraged

for our heart's sake

to eat more margarine in order to

stabilize that margarine

these vegetable oils were hydrogenated

which created

trans fats so in our effort to protect

our heart

we are actually eating the trans fats

that are now known

to cause heart disease in the 1980s and

1990s

all the nutritional authorities the

doctor kept

emphasizing that you should eat very low

fat

but slowly over those decades it was

clear that this initial gas

because there was no evidence to

actually support that was not

correct in 1997 a very large study

called the nurses health study out of

harvard

showed that no matter how much fat you

ate

it wasn't related to the risk of heart

disease

in 2001 top researchers

from the harvard medical school wrote

it is now increasingly recognized that

the low fat campaign

has been based on little scientific

evidence and may have caused unintended

health

consequences we were starting to see

study after study that showed that foods

high in fat things like nuts avocados

olive oil the mediterranean diet for

example

were not unhealthy they were actually

extremely healthy

in 2009 another published extensive

review

of all the literature to date showed

that

total amount of fat you ate the amount

of saturated fat

and the amount of unsaturated fat

had no correlation to your risk of heart

disease

and the study shows that these hazard

ratios are close to one

which means that there's no risk or

benefit with eating any of these

foods other studies began to show that

eating more saturated fat

was actually protective against heart

disease and stroke

this study broke 58 000 people into

five different groups quintile 1 which

ate

the least saturated fat and quintile 5

which ate the most saturated fat when

they followed them over time

the group that ate the most saturated

fat

had an adjusted odds ratio of about 0.7

to 0.8

meaning they had 20 to 30 percent

less heart disease less stroke and

less total mortality compared to those

who ate the least saturated fat looking

at these studies you might see

that eating saturated fat might actually

be protective

this reflects what was called in the

1980s and 1990s

the french paradox the french people

were eating a lot of whole fat

dairy and had a lot less heart disease

than other countries so this seemed to

be paradoxical

if you thought that saturated fat cause

heart disease

how could these people eat so much

saturated fat

and not get heart attacks and the answer

is quite clear in retrospect that the

saturated fat in these

natural foods was not causing heart

disease

and there was no paradox after all in

2017

the largest epidemiologic study was

published in the landsat

it covered 18 countries 135 000 people

and followed them over seven years it

measured

how much saturated fat total fat and

carbohydrates they ate

and compared that to the rates of heart

disease

you can see that the risk of heart

disease

looking at total fat and saturated fat

tended to go down as you ate more

saturated fat when you look at

carbohydrates

as you ate a higher and higher

percentage of your diet from

carbohydrates

the higher your risk of heart disease so

eating the fat did not seem to lead to

heart disease but eating a very high

percentage of carbohydrates

might in fact do that the conclusion

from a review by these heart specialists

of all the evidence that has accumulated

over the last 50 years

is that eating more natural fats

and natural saturated fats such as

might be recommended in the keto diet

for example

is not going to lead to more heart

disease

but in fact could be protective against

stroke

and if you're doing well with it and

losing weight there's no reason

to think that you're going to have

unhealthy consequences

whole fat dairy has also been linked

to less diabetes so as opposed to our

previous recommendation of making sure

you ate low-fat dairy if you eat

full-fat cheese full-fat milk

it does not lead to an increased risk of

heart disease

but could protect you against something

like diabetes which

does raise your risk of heart disease

and that's why the ketogenic diet

has been favored by some physicians

thanks for watching if you learned

something

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learn something too

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button and i'll see you next week