Couldn't find what you looking for?


HI, Gee Whiz, I seem to have different insulin to carb ratios at different times of day. Is this normal. I tend to eat the same amount of carb per meal but not always. It seems to me that breakfast is low in carb, my lunch is higher and dinner is lower and of course I eat different foods with my carbs at each meal. You know like bacon and eggs and fruit. Whereas, lunch is lots of green veggies and some cheese and less protein. For dinner I have more protein and a lot less carbs. So, you're insulin to carb ratios can vary throughout the day? Anyone know about this? Thanks.


Hi, You have to remember that everyone reacts differently to insulin such that no two individuals will have the same carb-to insulin ratios. Generally, a single unit of fast-acting insulin will cover 15 grams of carbs but ultimately it depends on other things you eat with your carbs. Protein and fats factor into this as well.


Your diabetes manager or doctor will establish a base line for you in terms of a carb-to-insulin ratio and then that will have to be altered over time by looking at your blood sugar levels before and after meals. This typically varies with breakfast, lunch and dinner and any snacks you have. There is something called the 450/500 Rule that is used to estimate what your ratios should be. This is true for type 1's for the most part. Type 2's are generally still producing some insulin so a total daily insulin dose can not be calculated reliably.

The 500 rule has been specified for individuals who use humalog and novolog and it is simple enough. You just divide the number 500 by your total daily insulin dose. What you get out of this is the carb grams that are covered by 1 insulin unit.


If you use regular insulin then go by the 450 rule. In this case you divide 450 by the total daily insulin dose. This also returns the carb grams that will be covered by 1 insulin unit.


I know I have different carb ratios at different time of the day. My breakfast ratios run around 1:8 while my lunch and dinner run around 1:10. Before I go to bed it runs about 1:12. You can see there is quite a difference. But, that has to do with what I eat.