I was just prescribed metformin due to my body not producing enough insulin. What "diet" should I follow?

Low carb diet. You probably have diabetes and need medications to control blood sugars. Diet and exercise can help tremendously along with medications. In general stay away from carbohydrates - i.e. Sweet things as well as drinks with too much. Eat more vegetables and whole grains, less white carbs and saturated fat. Also need to exercise daily 30min - aerobic and resistance. (www.Chrisohmd.Com).