What Happens When You Fast?

Hello Health Champions.

Today I want to talk about what really happens in the body when you’re fasting.

Coming Right Up.

Hey I'm Dr. Ekberg I'm a holistic doctor and a former Olympic Decathlete and if you want to

truly Master Health by understanding how the body really works make sure you subscribe

and hit that notification Bell so you don't miss anything we've been told for so long

that it's so important to eat to keep your energy up that if you don't have breakfast

you won't have any focus in school or at work but if that was true then anytime we try to

fast we would just get weaker and weaker and energy would fade away until we just

had nothing any time we try to fast but that's not how it works so instead how it works is

the body has these amazing mechanisms a backup to provide a constant supply of energy pretty

much no matter what happens because our food supply has not always been as consistent it

is today the first thing that happens when you eat something is that that food has to

be processed you put it in the stomach and now it has to be digested and absorbed. It's in

the bloodstream then it gets into the cells and some of that fuel gets used up in the

moment and some of it get stored so if we eat a lot of carbohydrates then most of that

in the beginning is going to be glucose so we're going to use a lot we're going to use

as much as 40 grams per hour of glucose and part of that is just to get rid of the glucose

and part of it is to process through it quickly so that we can store whatever we're not using

in the moment and the storage form for glucose is called glycogen and most of that is going

to end up in the muscles and some of it is going to also be stored in the liver for the

first 12 to16 hours after a meal if we don't eat again then glycogen is going to be broken

down and it's going to provide most of the glucose for the body for the brain and the

tissues But as time goes on the body is going to start looking for another source it's going

to start making glucose from scratch that's called gluconeogenesis and if we add up those

two sources the glycogen and the gluconeogenesis how much were using from each then you'll

see with this pink line that it's pretty constant in the beginning we just kind of breaking

it down but from 6 hours on up to about thirty hours then we're depending mostly on glucose

unless we are fat adapted so this example the initial example is for someone who's eating

a modern diet with high carb and frequent meals and then this is what it's going to look like

Over time though the body is going to start using more fat in the beginning it's

pretty low fat consumption But as time goes that we're not eating then insulin goes down

and we're going to start breaking down some of that fat and then also we're going to start

making more ketones as the glucose goes down as glucose becomes less and less available

now is when the ketones really kick in because that's the alternative fuel for the brain

to initially all the tissues in the body use glucose they use as much as they can firstly

just basically to get rid of the stuff but also because it's so widely available it's

so abundant then in Phase 2 and 3 we're relying on glycogen and gluconeogenesis and now the

body is still using mostly glucose but it's starting to turn more into fat burning gradually

the brain red blood cells and a portion of the kidney called the renal medulla is still

using pretty much 100% glucose the brain because it hasn't adapted to ketones yet and the red

blood cells and the kidney because they don't have any mitochondria They can't burn

fat for fuel but then as we get into the second day and beyond now the body has shifted and

it's burning almost exclusively fat Almost 100% of the liver and muscles and the other

tissues are using fat for fuel because the glucose is being spared for those tissues

that can't use fat so the red blood cells and the renal medulla are still using glucose only

the brain however it is gradually starting to shift. So in the beginning of this phase when we just get into day 2

and if you're not already fat adapted then it's still uses mostly glucose but toward

the end of it as we get in today 3 4 and 5 now the ketones have become dominant and if

you're fat adapted and you go beyond 72 hours now your ketones are going to provide about

75% of the fuel for the brain so how does the body do gluconeogenesis where does that

new sugar come from well there's different glucose sources so first we have glycogen

and that's not really gluconeogenesis because it's already glucose is just stored in another

form. Then we have lactic acid and pyruvate and those are byproducts of breaking down

glucose for energy when we don't have enough oxygen so either those tissues the red blood

cells or the kidney when they can't use fat or when muscles are working at a high intensity

when there's not enough oxygen then we're using glycolysis and we get lactic acid and

pyruvate so even though this is classified as gluconeogenesis in the textbook I don't

think of it strictly as gluconeogenesis it's not making glucose from scratch because

this stuff was already glucose it is sort of a net-zero game where it's just being hauled

around and converted in different tissues when I talk about true gluconeogenesis that

way I look at it is when the body makes glucose from something that was never glucose and

now it's making it from amino acids or glycerol amino acids is from protein and glycerol is

the backbone of fat it's a portion of fat so when we're burning fat we get some glycerol

freed up and that can be converted into glucose and this is what a lot of people are afraid

of with fasting they hear that when making glucose from protein and they think wow now

we're breaking down muscle I don't want that to happen but it's not really what's happening

can happen a little bit but it doesn't happen much and there's ways to avoid it so in the

beginning before we are fat adapted now there is going to be between eight hours and into

24 hours or so then we are mostly going to break down amino acids for glucose because

we're not fat adapted yet so the glycerol is not really available but first of all it's

a limited-time and secondly it's not all muscle tissue some of this is loose skin and some

of it is old dead cells and some of it is just junk and debris and pathogens in the

body that we're trying to get rid of and then something else happens which is autophagy

and an increase in growth hormone so already after about twelve hours we have a significant

increase in growth hormone and this keeps growing over the next week so that after two

days we already have a five-fold increase in growth hormone and this does two things

both autophagy and growth hormone kind of work together and they make the body better at

recycling and they also promote fat burning and when we burn more fat we make more

glycerol available so now we have that to make glucose from but growth hormone also build muscle

it is muscle sparing and autophagy and growth hormone put together prioritizes using protein

for structural tissue not for fuel so even though we can burn a little bit of muscle

for the first few hours of gluconeogenesis that's not an ongoing process and in the long

run there is very very little loss of muscle the body is way too smart to be burning

protein for fuel when there is any fat available and then in Phase 4 and 5 some other really

cool things happen these are all the benefits from fasting we get an increase in brain derived

neurotrophic factor BDNF which together with growth hormone is like Miracle Grow for the

brain what that means is anytime you learn something you make new connections you rewire

your brain anytime you repair something you rewire your brain and this happens exponentially better

when we have more of these hormones

so fasting and autophagy is some of the best things that we can have for repairing and

improving the brain, We further improve immunity and once we get past the 48 into 72 hours

now the stem cell production which is involved in body repair and healing increases tremendously

they eat a bunch of carbs they eat frequent meals. They're probably a little overweight and insulin resistant

this is how long it's going to take them to get truly fat adapted to where their systems

are really stable and just going on in a steady-state

but it's going to take that long whether you fast or whether you get fat adapted some other way

so if you do a low-carb diet or keto diet then you're going to get fat adapted

this this keto curve this keto production curve of ketones it's going to be pretty high

it's going to be readily available on an ongoing basis so if you are fat adapted and you're keto-adapted

then you're pretty much never going to leave phase 4

you're going to eat here and there your body is going to build up some glycogen for emergencies

but you're still going to have that metabolic flexibility that you're pretty much just going to exist in Phase 4

so what I recommend people do based on our knowledge of all these benefits

is if you have reached a health state if you reached a weight that you're happy with then

you're looking for maintenance and now what you do if you maintain a low-carb high-fat

diet which again where you are on that scale is low carb 30 grams or 50 or 80 it's going

to depend on you and you got to figure out where you are I also recommend that you do

some form of intermittent fasting it could be a 16/8 or an 18-6 meaning you eat for 6

hours during the day and you fast the other 18 and depending on how easy or hard it

is for you to gain weight or lose weight some people lose too much weight and some people

put weight back on so therefore you're going to probably alternate somewhere between 18-6

and omad depending on the person I can't do omad all the time because I lose too much

weight but I want the benefits of this extended fasting so I alternate between these two and

then what you can do is make a longer fast once or twice a month so if you have dinner

at 6 and then you don't eat at all the next day and then you have breakfast you had a

36-hour fast if you skip breakfast go to lunch you got a 42 hour fast and I think it's a great

idea to do this once or twice a month then a couple of times a year maybe once a quarter

maybe twice a year you do a longer fast because if you go beyond 3 days now you're getting

into some serious stem cell production some deep states of autophagy and repair.

And this is pretty much what I do this is what I would recommend for maintenance however if you are

looking to reverse a condition maybe you have a disease maybe you have some obesity maybe

you have some cancer or some autoimmunity now you just want to do maybe a little bit

more you don't have to if this does the trick for you then just do that but if you notice

that that weight still won't budge then you do a little more as needed so now maybe you

do more OMAD maybe you skip the 18:6 altogether maybe you do 18:6 once a week

maybe you do the 36 to 42 hour fast once a week instead twice a month and maybe you do

the three to five days all the way up to seven or ten days and you do that once a month or

every six weeks or something like that. So there's no hard and set rule for how to do this.

You gotta figure out how your body works and how are you feeling when you do these things and most

importantly don't rush into it do this gradually learn how your body functions learn how it

feels and then you move on from there

if you enjoy this video you're really going to love that one next thank you so much for watching and I'll see you next time.