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Effect of use of Metformin on Fasting days (5/2 diet).

Discussion in 'Type 2 Diabetes' started by LezLezLez, Jan 13, 2016.

  1. LezLezLez

    LezLezLez Type 2 · Member

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    I was recently shocked into increasing my attention to controlling my blood sugar - I am Type 2 Diabetic - prescribed and taking 4x500mg = 2g Metformin every day. The "shock" was based on one TV program in on 9th Nov. 2015 and I immediately commenced fasting on two non-adjacent days every week, in addition to improving my adherence to improved diet. I am currently following up my GP agreement that I can use the Low-Carb diet recommended to me by Diabetes UK. My question is this - I take 4x500mg Metformin tablets spread through my fasting days. Sometimes I feel "queazy" on these days and my blood glucose meter strips indicate my levels fall on these days to around 4mmol/L. Is this too low? Should I ask my GP to reduce my Metformin usage when my glucose levels fall below some level? My regular glucose levels average 7mmol/L over a 30-day period.
  2. Mafat

    Mafat · Well-Known Member

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    I am on fasting regimen with LCHF + HIIT & I was advised not to take Meformin & other sugar lowering medicines. You may read medical experts advise here :


    I first began with 3 days fasting a week with a Sunday night to Tuesday morning, Tuesday night to Thursday morning and Thursday night to Saturday morning. I drank coffee with cream in the morning when fasting, and water with a slice of lemon in it the remainder of the day. I ate egg and bacon in the mornings at first as I have always been told you have to eat breakfast! Later on the more I read the more I learnt that you don’t need breakfast so I changed my fasting regime and only ate one meal in the late afternoon. However, my glucose levels continued to drop at night so I quit all injected insulin, but continued the Glucovance with fasting and LCHF/Paleo type eating (REAL FOOD). By now my weight was slowly coming down and the needle on the scale was less than 90kg. I now weighed 87.8kg and had lost a total of 6.2 kg (2.9%) body fat and a total of 35cm.

    November 2015
    In April I went to visit my family in Texas and did not deprive myself at any time, however, I tried to make wise food choices, (not eating fries or the bun of a burger, no sodas, etc) and fasted when I had gone over-board. I took along my insulin, just in case, but didn’t need it; however, I continued using the Glucovance and continued to get very low glucose levels at night.

    On my return, I changed back to Metformin 500mg twice a day and continued with the HIIT, more intense fasting and LCHF/Paleo. Then on reading one of the question and answer sessions with Dr Fung on www.dietdoctor.com I realized that I should not be using Metformin on fasting days, so I quit that too.
    #2 Mafat, Jan 13, 2016 at 8:42 PM
    Last edited by a moderator: Jan 13, 2016
  3. 4ratbags

    4ratbags Type 2 · Well-Known Member

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    On days when you are fasting it would make sense not to take the Metformin for one it shouldnt be taken on an empty stomach and two, your levels seem to drop significantly on those days. Im sure if you discussed this with your Dr he would see the sense in just taking the Metformin on the days you are eating. Also with time your levels may continue to drop and if they do you may have to discuss reducing your meds even more.
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