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wasnt sure where to post

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my question is regarding different nutrients
and what our body will live on
specifically being the fat carb ratio

well if we lower the carb intake and eat more fat
we force our body into keto possibly
but wont our body just then live off new fat
instead?
like when does it live off our own fat?
wont it just live off what we put in it?
whether it be protein fat or carbs?
(i mean in the case when 1 nutrient put in
is way higher than the others)
it isnt just a matter of switching the
macros around?
it still lives on what we put in?
when does it ever get to its own storage?

gosh i hope i asked this right
 
The body needs glucose for certain organs including the brain and tries to keep the blood glucose level at about 5mmol/L. If there is insufficient glucose from food being eaten, such as on a keto diet, then it makes glucose from its stored fat.
If we eat more carbohydrate or fat than we need it is stored as fat, if we eat less than we need the fat is brought out of storage and used up.
 
This doctor has a good way of explaining it "the wood shed"
 

At the start of a keto diet you first have to get the body used to burning fat over carbs. This is usually achieved by using up your stored glucose and not adding extra. This can take anywhere from a few days to a few weeks.

Once you have done that then you could start some fasting to get your body used to burning body fat rather than dietary fat whilst still eating enough. i.e. reduce your eating window but not the amount you eat.

As for dietary carbs they are not essential at all so you don't need to put any in. The body can produce any glucose it requires (which is very little) using its own processes. Gluconeogenesis.
 
Mr_Pot said:
I can't see that your reference mentions fat storage. Dietary fat in the form of triglycerides is stored in adipose tissue. According to your statement even if I ate vast quantities of fat I would not put on any weight.
Click to expand...
This was taught to me in O level biology.

Eating "vast quantities" of fat - it's the basis for the keto diet, after all. Similar considerations apply for protein. You might gain weight but it wouldn't be body fat.

I have been on ~20g carb/day for just under 2 years now - no idea what my calorific intake is but I eat when I want, and as much as I want. I have not ever been hungry. This diet involves a lot of protein and fat. I have lost around 20kilo and about six inches off my waist.

The point about triglycerides is that these are one of the products of fat digestion and are stored in existing adipose tissue, which we all have. I've never seen anything that suggests triglycerides are what causes body fat. My triglycerides are bang in the middle of normal range.
 
A keto diet requires restriction of carbohydrates (varies between people but 20g to 50g per day gross carbs should put everyone into nutritional ketosis).
People normally initially consume low carb, moderate protein, high fat while there body gets used to burning fat (becoming 'fat adapted').
Once 'fat adapted' people normally reduce the fat consumed to allow some body fat to provide fuel (rather than mainly dietary fat). Carbs must be kept low, protein is moderate, fats make up the rest so you are not hungry.
Time restricted eating (eat at least once in each 24 hour period) forces the body to use body fat as fuel.
Fasting also forces the body to use body fat as fuel. If you decide to go this way then I suggest you do not exceed 1 week fasting

Note: you will need to adjust medications (particularly insulin) to prevent hypos.
 
Do you have any explanation of how "being fat adapted" actually works? Is there some physiological change? Surely we all burn fat or it wouldn't be a fuel and if we couldn't use stored fat we would just get fatter and fatter.
 
As a rule of thumb it’s not inaccurate to say that protein is the building material that keeps the machine in tip top order. The spare parts if you will. Carbohydrate and/or fat is the fuel that the machine runs on. The body can actually use all three for fuel because it will turn protein into glucose if necessary. Even if it means breaking down existing lean mass. It can also turn fat into glucose.

Personally I prefer to run with baseline glucose made almost entirely in my liver and drip fed into my bloodstream, primarily under the influence of glucagon. Therefore glucagon will be the dominant hormone in my system with insulin playing only a regulatory role. The opposite is true of most people eating a modern western diet where insulin always dominates.

Dietary fat can be stored directly in fat cells independently of insulin action. Both stored fat and dietary fat can be used as fuel without issue so long as insulin levels are not high. If insulin levels are high then glucose will always be the primary fuel because it’s toxic in excess and must be used or safely stored for a rainy day.

Yesterday I hadn’t eaten for around 18h and went on a pretty arduous 10km cross country hike over uneven ground uphill and down dale without once feeling hungry and still wasn’t hungry when I got home. It’s pretty amazing.
 
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Mr_Pot said:
Do you have any explanation of how "being fat adapted" actually works? Is there some physiological change? Surely we all burn fat or it wouldn't be a fuel and if we couldn't use stored fat we would just get fatter and fatter.
Click to expand...

I think the first major requirement is that circulating insulin levels need to be below a threshold. To be fat adapted your metabolism must be able to quickly and efficiently oxidise fat fast enough to produce the ketone bodies at a rate the body is able to use for energy. It cannot do this in the presence of elevated insulin. This is why obese people with hyperinsulinemia can run a hundred laps around the block and will get hungry rather than burn any meaningful fat. Hyperinsulinemia tends to be systemic over long periods and doesn’t simply rise and fall back to normal after eating carbohydrate.
 
Mr_Pot said:
Do you have any explanation of how "being fat adapted" actually works? Is there some physiological change? Surely we all burn fat or it wouldn't be a fuel and if we couldn't use stored fat we would just get fatter and fatter.
Click to expand...

Stephen Phinney and Jeff Volek found it took a number of weeks for athletes to adapt to a low carbohydrate diet - I think they use the term keto-adaptation rather than fat adaptation (example here, here and here).
Insulin needs to be sufficiently low for adipose cells to release fats for use as fuel.

I would speculate that fat adaptation requires a reduction in insulin and an increase in mitochondria, but understanding what happens in different parts of the body is still a work in progress.
 
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