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At What Point Does the Body....

Listlad

Listlad

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Messages
3,971
Type of diabetes
Prediabetes
Treatment type
Diet only
At what point does the body say right I am not burning carbs right now but will burn fats instead? Is it as and when there are no carbs left to burn or at some other time before that?

Thanks.
 
It takes a few days, up to a week, to get into ketosis, from the moment you start eating (less than/up to) 20 grams of carbs a day. You can tell by, at first, increased urination, and should you have them, try testing for ketones with a keto-stick. (Pee tests are cheaper than the blood strips) You don't have to, but it gives a bit of an answer quicker. You may also have an odd taste in your mouth, and smelly acetone/fruity breath. Not the best thing for one's love life, this close to Valentine's no less, but it's worth it.
 
JoKalsbeek said:
It takes a few days, up to a week, to get into ketosis, from the moment you start eating (less than/up to) 20 grams of carbs a day. You can tell by, at first, increased urination, and should you have them, try testing for ketones with a keto-stick. (Pee tests are cheaper than the blood strips) You don't have to, but it gives a bit of an answer quicker. You may also have an odd taste in your mouth, and smelly acetone/fruity breath. Not the best thing for one's love life, this close to Valentine's no less, but it's worth it.
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So it is simply a case of if the body is taking in only a small amount of carbs over several days that it kicks in?
 
With the caveat that I don't have a clue what I'm talking about.....

My thoughts are that the body will always use the easiest source of energy to burn, so Carbs first, then the body fat that was laid down from the excess carbs ingested, then the fat you eat. Of course protein can also be used as energy, so that must be factored in as well.

P.S. Some people use the term "fat adapted" but I have no idea what that actually entails
 
Listlad said:
So it is simply a case of if the body is taking in only a small amount of carbs over several days that it kicks in?
Click to expand...
@britishpub beat me to it. But yeah... The body will grab whatever is on hand to burn. If you haven't put carbs in, it becomes fat-adapted, and starts burning fats instead. it just takes a little while to shift, but it does. It really is that simple. Only real drawback I've found is keto-flu. And that doesn't last long anyway, and the benefits outweigh those few days of being achy a LOT.
 
Listlad said:
So it is simply a case of if the body is taking in only a small amount of carbs over several days that it kicks in?
Click to expand...
More than several days.. You have to effectively have burnt off most of your stores of sugar and not continued to "recharge" them. To become fully "fat adapted" which is when your body would start burning off body fat can take anywhere from 4-8 weeks depending on the levels of stored glucose (when you are T2 its been shoved into just about every cell in the body!).
As someone with pre-diabetes it's possible that it could happen faster in your case but it can be hard to identify. A lot of people report that they start to fast fairly effortlessly when fat adapted as they just don't feel hungry any more.
Does that help a bit..?
 
Glucose is often referred to as the 'preferential' fuel.
This doesn't mean that glucose is superior to other fuel sources.
It just means that glucose gets used first, rather like someone tidying up their desktop before they tidy the filing cabinets. ;)

So really, the body uses up available glucose from the blood, and storage around the body, such as glycogen in the liver and the muscles. Only when those stores are very low, will it start to draw on ketones.
And even then, if we eat carbs, then the body will tuck any excess back into the stores in muscles and liver BEFORE it converts the glucose to fat storage in the cells.

Therefore, it all depends on a few things:
- How much glycogen storage you have (often referred to as 'a couple of pounds' but Voleck and Phinney say that it is highly variable from individual to individual, and some people have difficulty in entering Ketosis because their body has learned to store 4 or 5 pounds of glycogen and water, rather than the usual 2 pounds. See The Art and Science of Low Carb Living for details on the relevant study).
- how much muscle mass, and how active you are, in order to burn through the available glycogen stores
- how much carb you are eating, which is replenishing the stores
- how much insulin resistance you have (this affects both fat storage and fat retrieval)
- how 'fat adapted' you are. Once fat adapted, it is much easier and smoother to switch from glucose burning to fat burning, and back again.

Short answer: How long is a piece of string ;)
 
JoKalsbeek said:
@britishpub beat me to it. But yeah... The body will grab whatever is on hand to burn. If you haven't put carbs in, it becomes fat-adapted, and starts burning fats instead. it just takes a little while to shift, but it does. It really is that simple. Only real drawback I've found is keto-flu. And that doesn't last long anyway, and the benefits outweigh those few days of being achy a LOT.
Click to expand...
Thanks for the explanation. So there is no halfway house. It is like flicking a light switch when it happens?
 
Listlad said:
Thanks for the explanation. So there is no halfway house. It is like flicking a light switch when it happens?
Click to expand...
It doesn't happen that quickly. Transitioning takes a few days. But yeah... The crossover happens relatively fast.

No halfway house... As long as you're moderately low carb, the body is burning carbs for fuel. Drop lower than 20 grams and the body shifts gears. It's like a tilting point, a watershed moment. :)
 
bulkbiker said:
More than several days.. You have to effectively have burnt off most of your stores of sugar and not continued to "recharge" them. To become fully "fat adapted" which is when your body would start burning off body fat can take anywhere from 4-8 weeks depending on the levels of stored glucose (when you are T2 its been shoved into just about every cell in the body!).
As someone with pre-diabetes it's possible that it could happen faster in your case but it can be hard to identify. A lot of people report that they start to fast fairly effortlessly when fat adapted as they just don't feel hungry any more.
Does that help a bit..?
Click to expand...
I see so it could well take longer than just a few days.
 
Listlad said:
Thanks for the explanation. So there is no halfway house. It is like flicking a light switch when it happens?
Click to expand...

Not really unless you stop eating all carbs and never touch them ever again.. then that may be the case but you will still likely be taking some in even if "low carb". The body will burn off those carbs first then go back to the fat use so depending on the amount of carbs and what your activity level is that may take more or less time .
 
JoKalsbeek said:
It doesn't happen that quickly. Transitioning takes a few days. But yeah... The crossover happens relatively fast.

No halfway house... As long as you're moderately low carb, the body is burning carbs for fuel. Drop lower than 20 grams and the body shifts gears. It's like a tilting point, a watershed moment. :)
Click to expand...
Gotcha there.
 
Ludwig reckons three weeks to become ketotic (nutritionally speaking). After becoming fat adapted then a metabolically flexible person switch in and out of ketosis in a matter of hours. For those of us with a metabolic dysfunction fat adaptation is optimal for obvious reasons. So we hear of members saying '.... may have knocked me out of ketosis for a couple of days...' having had a bit of a carb splurge but they are the fat adapted ones.
 
bulkbiker said:
Not really unless you stop eating all carbs and never touch them ever again.. then that may be the case but you will still likely be taking some in even if "low carb". The body will burn off those carbs first then go back to the fat use so depending on the amount of carbs and what your activity level is that may take more or less time .
Click to expand...

Thanks.

So activity level comes into it too...

Silly question really but trying to get my head around it.
 
bulkbiker said:
Depending on how deep you want to dive you might find this interesting
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Okay thanks, it was a case of trying to predict when it might happen. And if it might be achievable for me with my diet and aspirations etc etc. Rather than an academic exercise. I shall watch that video. Cheers.

I don’t know if you watched the Pink Panther but his “assistant” was called Kayto but pronounced Keto.
 
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