The best way to match insulin doses with meals is to perform carbohydrate counting – adjusting your dose for what you eat and not adjusting what you eat to suit your insulin dose. If you’re not doing carb counting, we would strongly recommend doing the New Deal course or 3 hour carb counting course.
Matching the dose – what factors are important?
- Over time people gain experience in estimating the carb content of the foods they most commonly consume. The more you do it, the better you get. The mobile app (and book) ‘Carbs and Cals’ is a convenient reference to help with this.
- The required ratio of insulin to carbohydrate is different for each person and, even in the same person, can be different at breakfast (where sometimes more insulin is required) than with later meals. A rough guide to the expected insulin to carb ratio is provided in Appendix 2. The ratio can also change over months and years – so it is worth assessing this periodically.
- Timing of quick- acting doses can be important and is discussed more is step 5.
Is my matching working?
- The first thing to do is make sure your background insulin is appropriate (step 3) – once you’re happy with this.
- Checking a glucose level before a meal, two hours after eating and before the next meal can provide very useful information:
- If the two hour level is high (it should ideally be less than 8) this may mean your ratio needs to change to give more insulin (if dropping low at 2 hours – a reduction may be required).
- If the two hour level is high but drops low at 4 to 5 hours- this may mean the timing of the quick acting insulin needs adjusted (i.e. to be taken further in advance of the meal).