You are doing only 1/3 of what is necessary to control and manage your glucose levels. Maintaining normal body and
daily 30-60 minute exercise must be undertaken. As you know,
diet alone does not do the trick. You must adhere to all three - diet, weight, and exercise.
And, yes, illness can spike glucose levels.
I don't know what you mean by "if one can eat more normally by taking Metformin". If you mean return to your old eating habits that created your diabetes, absolutely not.