New Science on Best Fasting Length for Fat Loss (12 Hours Through 72 Hours)

Summary

This video discusses the impact of fasting on metabolism and fat loss. It highlights the importance of maintaining muscle mass and adequate protein intake to keep metabolism high. The script reviews studies on 12, 36, and 72-hour fasts, revealing that a 36-hour fast can increase metabolic rate, while longer fasts show little change. It also addresses the dangers of chronic caloric restriction, suggesting that intermittent fasting with breaks can prevent metabolic slowdown and promote fat burning and autophagy for long-term health.

Takeaways

• 🔥 Prioritize maintaining a high metabolism for fat loss, which includes adequate protein intake and muscle maintenance.
• 📈 A 36-hour fast can increase metabolic rate, while a 12-hour fast may have little effect and a 72-hour fast shows no significant change from a 36-hour fast.
• 💧 Staying hydrated with electrolytes during fasting is crucial as it helps replenish minerals lost due to lower insulin levels.
• 🍊 Element electrolytes offer a variety of flavors that don't break the fast and can enhance the fasting experience.
• 📉 Extreme caloric restriction can lead to a significant drop in resting metabolic rate and a reduction in skeletal muscle mass within just three weeks.
• 🏃‍♂️ Intermittent fasting, if not paired with proper nutrition, can inadvertently lead to caloric restriction and metabolic slowdown.
• 🚫 It's not practical or advisable for everyone to undertake frequent 36-hour fasts.
• 🔄 Non-consecutive 24-hour fasts can improve glucose tolerance without causing a metabolic slowdown.
• 🔄 Regularly alternating between fasting and non-fasting periods can help prevent chronic caloric restriction and metabolic slowdown.
• 🌟 For long-term benefits, it's important to find a fasting method that can be sustained as a lifestyle without causing a permanent decrease in metabolic rate.

Q & A

What is the primary goal when considering fat loss and fasting?

The primary goal is to maintain a high metabolism, which includes maintaining muscle mass and adequate protein intake.

What did the study published in the British Journal of Nutrition find about different fasting durations?

The study found that a 36-hour fast increased metabolic rate, a 12-hour fast had little change, and a 72-hour fast had practically no change from the 36-hour fast.

What is the significance of the metabolic rate increase during a 36-hour fast?

An increase in metabolic rate during a 36-hour fast means that the body is burning more calories at rest, which can aid in fat loss.

What is the potential downside of continuous caloric restriction as seen in the American Journal of Clinical Nutrition study?

Continuous caloric restriction can lead to a decrease in resting metabolic rate and a reduction in skeletal muscle mass, which can slow down metabolism.

How much did the resting metabolic rate decrease in the study from the American Journal of Clinical Nutrition?

The resting metabolic rate decreased by 266 calories, with 8 of those being from adaptive thermogenesis.

What is adaptive thermogenesis and how does it relate to fasting?

Adaptive thermogenesis is a physiological response where the body reduces its energy expenditure during periods of low food intake. It relates to fasting as it can cause the body to slow down its metabolism to conserve energy.

What is the suggested approach to fasting to avoid metabolic slowdown?

The suggested approach is to avoid daily fasting and instead consider intermittent fasting with breaks, such as fasting for 24 hours on non-consecutive days.

How does the journal Endocrinology study relate to glucose tolerance and fasting?

The study found that doing three 24-hour fasts on non-consecutive days improved glucose tolerance without causing a metabolic slowdown.

What is the 'sweet spot' in fasting that the video script suggests finding?

The 'sweet spot' is the optimal fasting frequency and duration that prevents metabolic slowdown while still providing the benefits of fasting.

Why is it important to take breaks from fasting according to the video script?

Taking breaks from fasting is important to prevent the body from continuously slowing down its metabolism, which can lead to frailty and weakness.

What does the study in Cell Reports suggest about long-term adherence to caloric restriction?

The study suggests that the longer one can adhere to caloric restriction, the more benefits such as fat burning, autophagy, and heat shock protein effects can be achieved.

Outlines

00:00

🔥 Optimal Fasting for Metabolism and Fat Loss

The paragraph discusses the importance of maintaining a high metabolism for fat loss, emphasizing the need for adequate protein intake to preserve muscle mass. It introduces a study from the British Journal of Nutrition that analyzed the effects of 12-hour, 36-hour, and 72-hour fasts on metabolism. The study found that a 36-hour fast increased metabolic rate, while a 12-hour fast had little effect and a 72-hour fast showed no significant change from the 36-hour fast. The speaker also mentions the benefits of electrolytes during fasting, promoting a product called 'Element Electrolytes' that can be sipped without breaking the fast. The paragraph concludes with a teaser for another study that looked at the effects of caloric restriction and overeating cycles on metabolism.

05:00

🏃‍♂️ Balancing Fasting and Metabolism for Long-Term Success

This paragraph builds on the previous discussion about fasting and metabolism, suggesting that while daily fasting can lead to a slowed metabolism within 2 to 3 weeks, intermittent fasting with longer periods, such as 24-hour or 36-hour fasts once or twice a week, can actually increase metabolic rate. It references a study in the American Journal of Clinical Nutrition that showed a significant decrease in resting metabolic rate and skeletal muscle mass after just three weeks of caloric restriction. The speaker advises against continuous daily fasting, recommending a 'sprinting and resting' approach to avoid metabolic slowdown. A study in Cell Reports is mentioned, which supports the idea that long-term adherence to caloric restriction can lead to increased fat burning and other health benefits. The paragraph concludes with advice to find a sustainable fasting method that does not permanently reduce metabolic rate.

Keywords

💡Fat Loss

Fat loss refers to the process of reducing the amount of body fat while trying to maintain or increase lean body mass. In the context of the video, fat loss is the primary goal, and the discussion revolves around how fasting and metabolism relate to achieving this goal. The script mentions that whether one is fasting or not, maintaining a high metabolism is crucial for fat loss.

💡Metabolism

Metabolism is the process by which the body converts food into energy and uses it for various functions. A high metabolism is desirable for fat loss as it means the body burns calories at a faster rate. The video emphasizes the importance of keeping the metabolism high, avoiding actions that might slow it down.

💡Protein

Protein is a nutrient essential for maintaining muscle mass and is highlighted in the script as a priority for keeping metabolism high. Adequate protein intake is crucial during fasting to prevent muscle loss, which could otherwise lead to a decrease in metabolic rate.

💡Fasting

Fasting is the act of abstaining from food for a certain period. The video discusses different fasting durations (12-hour, 36-hour, 72-hour) and their effects on metabolism. It explores how fasting can be a tool for fat loss when done correctly and how it can impact metabolic rate.

💡Element Electrolytes

Element Electrolytes are mentioned as a product that can be sipped during fasting without breaking the fast. They provide essential minerals that can be lost during fasting when insulin levels are low. The script suggests that using electrolytes can enhance the fasting experience by replenishing lost minerals.

💡Caloric Restriction

Caloric restriction refers to the deliberate reduction of calorie intake, often used for weight loss or health benefits. The video contrasts fasting with caloric restriction, noting that while both can lead to weight loss, they affect metabolism differently. The study mentioned in the script shows that extreme caloric restriction can slow down metabolism.

💡Adaptive Thermogenesis

Adaptive thermogenesis is a physiological response where the body adjusts to conserve energy during periods of low food intake. The script cites a study where subjects experienced a decrease in metabolic rate due to adaptive thermogenesis after a period of caloric restriction.

💡Intermittent Fasting

Intermittent fasting is an eating pattern where individuals cycle between periods of fasting and eating. The video discusses the 16:8 method (fasting for 16 hours and eating within an 8-hour window) and how it can lead to metabolic slowdown if not managed properly.

💡Glucose Tolerance

Glucose tolerance refers to the body's ability to regulate blood sugar levels after consuming carbohydrates. The script mentions a study where subjects who did three 24-hour fasts on non-consecutive days showed improved glucose tolerance, indicating a positive metabolic response to intermittent fasting.

💡Autophagy

Autophagy is a cellular process where the body breaks down and recycles its own tissues, which can have benefits for health and longevity. The video suggests that maintaining a lifestyle of caloric restriction over a long period can enhance autophagy, contributing to the benefits of fasting.

💡Heat Shock Protein

Heat shock proteins are proteins produced in response to stress, including fasting, which can help protect cells from damage. The script implies that long-term adherence to caloric restriction can increase the production of heat shock proteins, offering additional benefits to fasting.

Highlights

Maintaining a high metabolism is crucial for fat loss, regardless of fasting.

Prioritize maintaining muscle and adequate protein intake to keep metabolism high.

Avoid actions that dramatically slow down metabolism.

A study analyzed 12-hour, 36-hour, and 72-hour fasts to identify metabolic changes.

36-hour fasts increase metabolic rate, while 12-hour fasts have little change.

72-hour fasts show no significant change from 36-hour fasts in metabolic rate.

Fasting for more than 36 hours does not provide additional metabolic benefits.

A caloric restriction study showed a decrease in resting metabolic rate and muscle mass.

Adaptive thermogenesis contributes to a slowed metabolism during extreme caloric restriction.

Intermittent fasting can lead to calorie underconsumption and a drop in metabolism.

Fasting has benefits beyond caloric restriction, such as improved glucose tolerance.

Three 24-hour fasts on non-consecutive days can improve glucose tolerance without metabolic slowdown.

Daily fasting and caloric restriction can slow metabolism within 2 to 3 weeks.

Fasting two days per week at 24 hours or one day at 36 hours can increase metabolic rate.

It's important to find a fasting method that doesn't continually slow down metabolism.

Taking breaks from fasting can help maintain a high metabolism over the long term.

A study in Cell Reports showed the benefits of lifelong caloric restriction for fat burning and autophagy.

It's essential to find a sustainable fasting method to avoid long-term metabolic slowdown.

Transcripts

if fat loss is your goal it doesn't

matter whether you are fasting or not

identifying what is going to keep your

metabolism high should be priority

number one now subcategories of that

priority number one would definitely be

maintaining muscle adequate protein

things like that right so that all falls

under that high metabolism category we

want to avoid doing anything that

dramatically slows down our metabolism

so I can jump right in and talk about a

interesting paper that analyzed a

12-hour fast a 36-hour fast and a

72-hour fast to help

identify when things kind of slow down

and when things speed up let's break it

down so after today's video I popped a

link down below for a free variety pack

of element electrolytes so with any

purchase from element you get a free

variety pack a sample pack so that you

can give out a bunch of different

flavors to your friends or just keep

them for yourself so if you're fasting

I'm telling you it is a game Cher when

it comes down to being able to have

something to sip on that isn't going to

impact your fast so they have citrus

salt flavor they have mango they have

mango chili they have lemon habanero

just tremendous flavors that are not

going to impact your fast as a matter of

fact they're going to improve your fast

because you're going to be getting those

electrolytes in which when you're

fasting insulin levels are lower and

you're losing minerals so it's a good

time to be bringing it in so anyway pop

that link down below and that's going to

get you that free variety pack when you

try them out trust me it'll change how

you fast so this the study that we're

looking at was published in the British

Journal of nutrition and it was a little

bit of an older study but I have a newer

study that I want to cross reference it

with so that we can understand some more

stuff what they ultimately found when

they investigated a 12 36 and 72-hour

fast is that a 36h hour fast actually

increased metabolic rate what that means

is that actually increased the

metabolism 12-h hour fast actually kind

of lowered it a little bit or didn't

have much change and a 72-hour fast was

practically no change from the 36-hour

fast so what this is telling us right

here is that above 36 hours we actually

don't get much additional benefit

outside of of course some fat burning

but we're not increasing our metabolic

rate now does this mean that everyone

should just go out and do as many 36-

hour fast as possible no not at all

because that's not really practical in

fact a lot of people watching this video

that might even be scary to embark on a

36- hour fast in the first place but

what we do need to do is look at another

paper that was published in the American

journal of clinical new nutrition and

this one looked more at just continuous

caloric restriction so they had subjects

overeat for one week and then they had

them go into a deficit quite

significantly a 50% caloric deficit for

about 3 weeks and then after 3 weeks

they had them do a two we caloric refeed

of 50% Surplus what they found is during

that 3w we caloric deficit they ended up

shrinking their resting metabolic rate

by 266

calories eight of which was from what's

called adaptive thermogenesis what this

basically means is that when they went

through extreme caloric restriction they

ended up slowing down their metabolism

and having a 5% reduction in skeletal

muscle mass this happened in literally 3

weeks now the reason that I mention this

is that this is likened to a traditional

168 intermittent fasting regimen when

people are not paying very close

attention to what they eat during their

eating window not getting enough

calories in undereating and putting

themselves in that caloric restriction

phase when people lose a lot of weight

with intermittent fasting right out the

gate particularly 168 if you analyze

their calories most of the time you find

they're eating a lot less that does not

mean that you're not getting benefits

independent of caloric restriction with

fasting because you are there are

benefits that come from fasting that are

completely separate and apart from

caloric restriction however a lot of

people that are fasting are still

restricting calories they're just not

necessarily realizing it

so the concern is that in 3 weeks you

can be plummeting your metabolism to

such a point whereas when we look at

this BR British Journal nutrition study

we see well relatively infrequent longer

fasts will actually increase the

metabolism so we need to find The Sweet

Spot here right how do we find that

sweet spot where our metabolism does not

slow down now with this we should also

reference another study that was

published in the journal Endocrinology

that found that when subjects did three

24-hour fasts on non-consecutive days it

also improved their glucose tolerance so

I did another video where I kind of

broke all these studies down to try to

find the perfect frequency of fasting

but what we're looking at here is like

at what point does your metabolism slow

down so with three uh non-consecutive

day 24-hour fast there are improvements

in how the body utilized glucose but

there weren't these issues with

metabolic slowdown so what we find here

is that if you are fasting essentially

daily and putting yourself in a caloric

restriction phase it takes about 2 to 3

weeks for your metabolism to slow down

whereas if you were to fast maybe two

days per week at like a 24hour fast or

one day a week at a 36- hour fast you

can actually increase metabolic rate

because it's such a shock to the body

and it's not chronic caloric restriction

you actually get this benefit but I

don't expect everyone to do that one day

a week that's not what I'm getting at

what I am suggesting is that if you're

doing daily

168 you have about two weeks before you

need to say hey I got to take a break or

I got to reduce my number of fasting

days and it's okay to do this in a

fashion where you're like sprinting and

then you're taking a break sprinting and

taking a break we have to continually

sort of shock the body a little bit

otherwise you're going to put yourself

in this metabolic slowdown this way you

can maintain doing this for a long

period of time and there was a cool

study in cell reports that demonstrated

that the longer just in terms terms of

your lifetime that you can adhere to

caloric restriction the more fat burning

effect the more autophagy and the more

heat shock protein effect you can get so

you continue to extract benefits if you

can make it a lifestyle you cannot make

it a lifestyle if you're shrinking your

met metabolism and your metabolic rate

forever and ever and ever that's just

not realistic you're going to become

frail and weak and you're not going to

feel good so find a method that works

for you but just do not continually fast

every single day for longer than about a

2 we period before you take a break I'll

see you tomorrow