On the prescribed high carb cholesterol reducing diet I was on - even though my cholesterol was not that high, I reached 264lb and had more of an equator than a waist.
On diagnosis I went straight back to eating low carb foods and my waist softened and shrank - I can honestly say that my waist sucks, as it shrinks down and then moves in more fat from elsewhere, but I have seen reductions of up to 12 inches, and my whole shape has changed. I can now wrap the kilt I wore twice around, instead of one and a half. I have also realized that my arms and legs, which used to be rather hairy are no longer, after some 40 years of long sleeves and thick tights or leggings.
You might find that the Glucophage treatment is too harsh if you impose a severely low carb or low calorie diet - HCPs often assume a high carb diet is obligatory, so take care not to cause hypos.