I recently had a drink with 124 grams of carbohydrates, 19 grams of fat and 23 grams of protein in it. It is important to know that two hours prior to this, I rode my bike for one hour and 45 minutes at a moderate-to-high effort. Now I will tell you how I adjusted and administered my insulin to make sure my blood sugar stayed level.
To cover the 124 grams of carbs, I divided 124 by 17 since one unit of insulin covers 17 grams of carbohydrates for me when I exercise like I did (when I do not exercise I use one unit for every 15 grams of carbs). So I took 7.3 units to cover the 124 grams of carbs. Since my drink had a “fair” amount of fat (22 percent) and protein in it, I new I would benefit from using a “square-wave” bolus on my insulin pump to deliver my insulin over time. This is because the fat and protein would slow the absorption of the carbohydrate into my system. I chose 30-minutes to deliver my dose based on past experience with “square-wave” bolusing. So my 7.3 units was delivered over a 30 minute period, which allowed my Humalog to be available longer than if I had taken it all at one time.
The thing I would like you to remember is that Humalog is really only active in your blood stream for about 3.5 hours. If you eat a meal high in fat and/or protein, your Humalog may not last long enough to cover the carbs that are delayed in entering your system due to the fat and protein in the meal. The higher the fat and protein content of your meal, the longer time period the insulin will need to be delivered over. Those not on pumps may find Regular insulin works better for these types of meals because it tends to stay active for about 5.5 hours.
Oh, and in case you were wondering, I was off by about one unit in my calculation for the peanut butter mood. I guess I exercised a little harder than I thought. I actually only needed 6.3 units, which would have made my insulin to carb ratio 1:20.