Like "I use the MyFitnessPal app to help me to estimate how many carbs are in the meal. I then inject about 1 unit for every 10-15 grams of carb. It's worth remembering that your body is probably still making some insulin, so monitor your sugars 2 hours after the meal and then you'll begin to develop a better understanding of the amount of insulin that your body needs for different foods and quantities of carb. "