if the sugar level,is about 8 before meal,and 13 after meal,and normal should be ~4-5,you need to inject (8-5=3,13-5=8. 3+8=11. 11:1,4=7,85.) 8 units of insulin.before meal.if sugar level will be 4-5 before meal,need to let 5.5-6 units of insulin for same amount of food.5-10 min before...