4 ms·

Not if you need glucose delivered quickly (i.e to help with the task at hand). http://www.bbc.co.uk/programmes/b03t8r4h http://www.bbc.co.uk/programmes/b03t8r4

Not if you need glucose delivered quickly (i.e to help with the task at hand). http://www.bbc.co.uk/programmes/b03t8r4h http://www.bbc.co.uk/programmes/b03t8r4h The body can't easily/quickly convert fat into glucose.

dredmorbius 12y ago
The body cannot convert fat into glucose at all.
- coldtea 12y ago
  You'd be surprised: """acetic acid (in the form of acetyl-CoA) is used to partially produce glucose; acetyl groups can only form part of the glucose molecules (not the 5th carbon atom) and require extra substrates (such as pyruvate) in order to form the rest of the glucose molecule. But a roundabout pathway does lead from acetyl-coA to pyruvate, via acetoacetate, acetone, acetol (hydroxyacetone) and then either propylene glycol or methylglyoxal."""
  - dredmorbius 12y ago
    What are the rates of this pathway? Minimum daily glucose requirements are on the order of 100g, possibly higher. If this pathway cannot sustain that delivery rate, it's not significant.
    - coldtea 12y ago
      Sure, and I didn't say otherwise. Just answered your initial comment that was "The body cannot convert fat into glucose at all". So it's a little moving-the-goalposts disingenous to brush this off as "it's not significant for our daily glucose requirements", when your initial claim was much stronger and this refutes it.
      - dredmorbius 12y ago
        Sorry, but you're apparently misreading my tone. As I'd indicated in another response, I wasn't aware of pathways other than straight carbs or synthesis from protein (and knew of but forgot about the glycolysis/pyruvate pathway). I appreciate the new information. https://news.ycombinator.com/item?id=8698478 https://news.ycombinator.com/item?id=8698478 My question simply as read: do you know of rates of production of this pathway? If it cannot meet ~100g/day or a significant fraction of that, then it's not really materially significant, though it is of interest. If it can, well, then, that changes things. Answering the question or stating "I don't know" would be acceptable.

dredmorbius 12y ago

The body cannot convert fat into glucose at all.

coldtea 12y ago
You'd be surprised: """acetic acid (in the form of acetyl-CoA) is used to partially produce glucose; acetyl groups can only form part of the glucose molecules (not the 5th carbon atom) and require extra substrates (such as pyruvate) in order to form the rest of the glucose molecule. But a roundabout pathway does lead from acetyl-coA to pyruvate, via acetoacetate, acetone, acetol (hydroxyacetone) and then either propylene glycol or methylglyoxal."""
- dredmorbius 12y ago
  What are the rates of this pathway? Minimum daily glucose requirements are on the order of 100g, possibly higher. If this pathway cannot sustain that delivery rate, it's not significant.
  - coldtea 12y ago
    Sure, and I didn't say otherwise. Just answered your initial comment that was "The body cannot convert fat into glucose at all". So it's a little moving-the-goalposts disingenous to brush this off as "it's not significant for our daily glucose requirements", when your initial claim was much stronger and this refutes it.
    - dredmorbius 12y ago
      Sorry, but you're apparently misreading my tone. As I'd indicated in another response, I wasn't aware of pathways other than straight carbs or synthesis from protein (and knew of but forgot about the glycolysis/pyruvate pathway). I appreciate the new information. https://news.ycombinator.com/item?id=8698478 https://news.ycombinator.com/item?id=8698478 My question simply as read: do you know of rates of production of this pathway? If it cannot meet ~100g/day or a significant fraction of that, then it's not really materially significant, though it is of interest. If it can, well, then, that changes things. Answering the question or stating "I don't know" would be acceptable.