Carb counting


ok aaron had the clinic last week and his hbaic is up to 9.5, hasnt been that high in years! dr increased the lantus at night by 1 unit and if bloods still high in a few weeks to increase it by one unit again.

no other advice was given at clinic and after doing some research and asking advice on a uk email list i have decided to carb count, have started a diary and listing all he eats, his bloods and the carbs he has eaten.

dont know how to adjust insulin yet to the amount of carbs so any advice/tips would be great.



I am curious myself. The dietitian I was referred to gave me a carb limit of 60 per meal and 30 per snack based on my current dosages. Since that, I have adjusted my insulin on my BG reading before each meal (assuming that I will max out on my carbs each meal.) I know this is not the best way to do it but it has worked ok for me but I am seeing the Endo at the end of this month and we will see what he has to say.


Counting carbs works very well. I took Lantus before going onto a pump. Now I use the Lantus on my diabetic cat. Are you using a fast acting insulin like Novalog? If so then counting your carbs will really help because then you can use the fast acting insulin to counteract the food you eat. Which plays right into counting carbs. When I used lantus I started off just using it 2 times a day. But I really got control from using the lantus and the novalog.


I’m not sure how the healthcare system works in Scotland, but is there some kind of diabetes educator you can meet with? They should be able to teach you how to match insulin with food. It’s especially useful with little kids since they don’t always like to eat the same amount from day to day.


Susan, carb counting is great to help with control. It can be a bit overwhelming at first, but once you get the hang of it it’s pretty easy.

For me I always know an average slice of bread is about 22 carbs, a ritz cracker is 2 carbs, a cup of milk is 12 carbs, etc. After a while you memorize the foods you regularly eat.

There are 2 approaches to using carb counting:

  1. Count carbs so you eat the same number for the same meal each day. If the BG is at a good level by the next meal/snack, then you are probably near the right level of carbs for that meals insulin injection.

  2. Adjust your insulin dosages every meal based on the # of carbs you’ll eat. This one requires that you compute a carb/insulin ratio. You should probably talk to your Dr. about that.


If you can get a hold of the book, Dr. Bernstein’s Diabetes Solution, he described one way to determine how low one unit of bolus insulin will lower your blood sugar.

If you know how much 1 unit lowers you, you can figure out how many grams of carbs that covers using the table he gives that relates weight to how high one gram of carbs will raise you. For a 140 lb person 1 gram of carbs raises you 5 mg/dl (.27 mmol/L). For a 70 pound person it raises them 10 mg/dl (.55 mmol/L).

So if 1 unit of Novolog dropped you 45 mg/dl and you weighed 140 lbs, you’d know 1 unit would cover 9 grams of carb. If 70 lbs, 18 grams.

Then you start out matching the insulin to the carbs you are going to eat using a ratio that errs on the side of leaving you too high, rather than too low, ie. if you thought the ratio was 1 unit of fast insulin to 15 grams of carbs, you might start out with 1 unit and 20 grams, just in case you were wrong, so you’d go higher, not lower. Then you work your ratio down until you get to the right dose.

Use a food that you can weigh on a food scale so you know exactly how many grams of carbs are in it when starting out. It’s best to start with a modest amount of carbs, too-so you use no more than 2 or 3 units of insulin so if you are wrong you don’t end up with a big problem.

Once you have a good idea of the ratio, remember it isn’t always going to hold true, for example, some people will need more insulin at breakfast time because most humans are more insulin resistant on awakening. It will also change with illness and other stresses.

Obviously, if you are going to count carbs, you also have to learn how much carb is in your food. This means weighing out portion sizes as given in nutritional books or databases. The portion size is often FAR different from what you would think of as a portion. This step is EXTREMELY important.

A muffin is often listed as having a 2 oz portion size, but the ones sold at bakeries are often 8 oz. You can see where counting carbs could be a disaster unless you can learn to correctly estimate the weight of your food and keep aware of the portion sizes in the nutritional guides.

It seems overwhelming, but over time it becomes part of your brain and is no big deal. I’m usually very close without needing to weigh anything after years of counting carbs.