On metformin bid for a week. metformin + low carb or no carb meal = lethargy. either no lethargy or not as much when not cutting carbs. why?

Metformin: Metformin alone does not cause your blood sugar to drop below normal unless you deprive yourself of the necessary amount of daily calories. I recommend that you consult a dietician at your local hospital for advice about a proper diet so that you don't deprive yourself of the daily recommended amounts of calories and carbohydrates in your diet.