Hi, How are you getting on with your 'Newcastle Diet'? How much weight have you lost and how much more is wanted?
Metformin even at maximum dose is unlikely to have a huge effect on your Blood Glucose.
The theory behind the diet is that the reduction in weight (which is mainly body fat) will reduce your Insulin resistance, which will make your own natural insulin more effective and thus reduce your Blood Glucose. There is another effect which varies a bit depending upon what the actual diet consists of i.e. how much Protein, how much fat and how much carbohydrates.
The fewer of the calories which come from carbohydrates, the lower your Blood Glucose is likely to be. - This is because all digested carbohydrates turn into glucose (both sugars and starches), so the more carbohydrates in your particular Newcastle Diet, the higher your glucose regardless of the total calories.
If your ND is low in carbs then it's probable that your liver is (at least occasionally) dumping glucose. Livers do that a lot until they get accustomed to lower glucose levels. That is what the Metformin is supposed to reduce and 3 weeks isn't that long,
I have not personally used ND, instead I used Low Carb for my T2 Diabetes control and remission. For me it was easier to adjust my carb intake in order to reduce my BG than to reduce my calories and hope that would reduce my BG.
Consistently high BG numbers during the day when not eating very frequently, sounds like a there may be non-food reason. There are many of these, but the most common include:
Injury
Illness
Stress
Lack of Sleep
Medication such as Statins or Steroids
