When is rapid-acting insulin preferable to regular insulin?

[Amelia.M]

I've been trying to understand the different types of insulin for my own management, but I'm confused about when a rapid-acting analogue is actually preferable to regular human insulin in a treatment plan. My doctor mentioned the onset of action, but I'm not sure I grasp the practical daily impact of that timing difference on things like post-meal spikes.

[Ryan35]

From my own trial I found rapid acting insulin starts working sooner so the peak comes with the meal. If I inject right before eating I see the glucose rise after the meal but then it falls more quickly than with the older stuff. It feels like less planning but the day to day variability still bites.

[Abigail_T]

With regular insulin I had to plan the injection thirty to sixty minutes before a meal to cover it well. If I ate sooner the spike was big and I had to shoot a correction later, which felt clumsy and less predictable. It worked for some meals but not for all and the variability was higher.

[Jonathan.D]

Do you think the main issue is timing or is something else about the meals you eat driving the spikes?

[AuroraWG]

One thing I did was keep a simple log for a week after switching to rapid acting. I noted the meal time the bolus time and the two hour numbers. The post meal spikes were smaller on some days but on high fat meals the late rise still showed up.