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How Low is Too Low on Extended Fast?

Discussion in 'Low-carb Diet Forum' started by droog, Jul 12, 2020.

  1. droog

    droog Type 2 · Member

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    I am a 55 yo male, type 2 (diag 2012) on Metformin only (2000mg extended release). Last two A1C: 30.1 mmol/mol (4.9%). Current weight 210 down from 400+ a few years ago. No complications. Diet: VLCHF, < 20gr carb daily. Well most days. ;)

    Fasting Regime: Water, tea, black coffee, vitamins & salts only.

    After 3-4 days of continuous fasting, I am in deep purple ketosis and my blood sugar typically hovers around 3.6 mmol/l (65 mg/dl). But occasionally has dipped down around 3.0 mmol/l (55 mg/dl), confirmed by two tests 10 minutes apart. When it is in the 50's I definitely feel low energy. Having blood sugar in the 50's concerns me and I break my fast.

    However, I have read that some experiments from decades ago demonstrated that fasting patients in ketosis showed no ill effects from blood sugars below 20 following injection of insulin. While I am understandably skeptical about that...

    QUESTION: How low is too low when on an extended fast?

    Thank you.

    Oh, anyone have a reference to the study I mentioned, I can't find it?
     
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  2. bulkbiker

    bulkbiker Type 2 · Oracle

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    I've experienced 3's usually on day 3 of a fast but it soon goes back up to the low 4's for days 4-7 (never gone for more than 7 days)
    The study you are looking for is I believe one of George Cahills of the 1970's where they injected people in deep ketosis with insulin to drive their BS levels down to the 2's with apparently no ill effects.

    I'll see if I have a link to it.

    Edit to add I think its this one but I haven' t read through it to check! Sorry cooking dinner

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2441301/pdf/tacca00109-0225.pdf
     
  3. droog

    droog Type 2 · Member

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    Bulkbiker,
    Thank you for your reply. I read through the document you posted. It didn't mention the experiment regarding inducing extremely low blood sugar during deep ketosis, but it was fascinating reading none the less.
    All the best,
    Droog
     
  4. LaoDan

    LaoDan Type 2 · Well-Known Member

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    Great work on the weight loss!!!
     
  5. MarkMunday

    MarkMunday Type 1 · Well-Known Member

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    Low blood glucose is a concern if there is excess insulin action driving it down. As you are not using insulin, IMO low blood glucose should only be a concern if you are not feeling well. The liver will supply enough glucose to keep you going until you end the fast..
     
  6. bulkbiker

    bulkbiker Type 2 · Oracle

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    Sorry about that I'll have another dig around. It was mentioned in a Phinney video and I'm sure I have a link saved somewhere...
     
  7. bulkbiker

    bulkbiker Type 2 · Oracle

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