Insulin Sensitivity

I have insulin-dependent diabetes, I take novorapid and levmir. When I stick to low-carb eating, I take about 2 - 2 1/2 units novorapid with each meal. The problem is that when I eat a little more, and take, for example 3 units, I very often go hypoglycemic. Its crazy, that the difference between 2.5 and 3 lowers my BG so much. And on the other side, 1 or maybe even 1.5 hardly affects the BG, so I have no way to bring it down just a little bit.
Does anyone have something like this?

In my experience, fast acting insulin like novolog and humalog are not a good match with ultra low carb eating. When you eat a large amount of protein and fat with your carb it slows down the amount of time it takes for the carb to be digested. This can lead to the low BG you are experiencing (and will often lead to a high BG later once the protein is being digested). One solution, if you want to continue to eat low carb, would be to try a different (slower) insulin, or to inject it later. Bernstein, in fact, recommends the use of Regular instead of Novolog/Humalog under some conditions as part of his ultra low-carb eating program.

I find that a moderate amount of carb (say 50g though of course this varies) mixed with protein and fat is a good match with novolog/humalog. So another solution would be to increase the carb in your mixed meals. YDMV of course. In general, you need to experiment and find what you prefer, and what works best for you.