This thread has some useful information, including a section about metformin. It's easy to forget that high blood sugar has other effects - such as causing eye problems.
For myself, my annual HBA1c readings since diagnosis with T2 have been (earliest first) 7%,51,53,48,44,42,40,41
The reading of 53 is about the time I switched from 2x500mg/day to 3 per day - at which point my HBA1c kept decreasing year on year. Dietary changes - just minor ones - have been reviewed each year. The reading of 40 was at my last annual review in Nov 2016 at which point I discussed with my GP a reduction back to 2/day, with a review after a few months. The reading of 41 was as of 3 weeks ago - my GP is as pleased with this as I am, so the reduced tablets will continue until my next review in November.
The period where it went down from 44 to 40 coincides with the time period when my wife retired. The difference - 4-5 times a week we go for a walk and have coffee and cake half-way through, something I didn't do in the time period up until then.
There has been a change of diet between November and now - that is slightly higher sugar intake (Christmas/new year!) and more carbs during the Winter and some cancelled exercise opportunities (shorter walks/bike rides in the cold/wet weather!). Because of this the November result (which will be preceded by longer walks/bike rides) should prove interesting.
From my viewpoint I would say the MF works. At first I did get the (warned-of) side effects -upset tummy, sweating etc - but these passed after the first few weeks.
How do you define minimal impact? - well, the impact of having one less slice of bread at teatime for a few months resulted in a weight reduction over that time of 1 kg. A tiny change, a minimal impact day-to-day - but a nice cumulative effect thank you. A bit like compound interest! Maybe "minimal" is all you need to make a difference over time.
Basically, do it and measure to see the effect.
