I was trying to work out how much carbohydrates for every unit of insulin I needed to take and how many mmol/l above target for every extra unit I needed to take. Here is the information I had: I consumed approximately 286g of carbohydrates over the course of a day, I took 23 units of fast acting insulin on that day and all that left me at the 7mmol/l you see in the photo. The 8 units there don't count because that is my long acting insulin dose I take every night at 10pm. I made a slight mistake in calculating the carbs per unit. I said 286÷23=1x instead of =x+1 (target reading + 1. The target is 6mmol/l). 286÷23=12.4 to one decimal place. It should have been 12.4=x+1 => 12.4-1=x=11.4. But having it at 12.4 allows for days that I'm more active when I would be a bit more sensitive to insulin so I'll leave it at 12.4g carbs per unit.
The next thing was working out how many mmol 1 unit of insulin covers. I wasn't sure how to do this but here's what I did. It'll give me a close enough rough guide. 23 units of insulin over the course of the day left me at 7mmol/l. 23=7x, 23÷7=x=3.3 to one decimal place. So take one unit for every 3.3mmol I'm above target. This may or may not allow for the amount of carbohydrates consumed but, like I said, it's good as a rough guideline. There are variables outside this that will affect what my reading is like snacking between meals which I don't test or dose for, how long after my last dose I snack (which can leave excess glucose in my blood when the dose wares off) and being more active than anticipated between meals (which can lower my glucose). So my calculations can't be 100% accurate. This rough guideline should help give me more control than winging it for the previous two years. "Should" being the operative word!
I have the time at the moment to research and work out the nutrients in dishes that aren't already in the food section of my health app and input them manually. Once I input info manually the app stores it for me for future use. Once any food has the nutrients in the app I can see how much carbohydrates in a meal as the app adds it up for me. I can calculate how many units needed then. If I didn't have the time I'd still be winging it and would say keep doing what works for you to anyone else who hasn't got the time to be working out carbs in a meal and calculating the amount of insulin to take with them. Another thing is I don't round up where the digits after the decimal point are closer to the number above (eg. 6.9 I'd take 6 units). When I first started counting carbs I was using 11g/unit, rounded from 11.1 and a meal had 40g of carbs. I took 4 units because it was closer to 44 than 33. I ended up going hypo just before my next meal. That is why I now go with the whole number and ignore what's after the decimal point when calculating units to cover a meal.
