Like I just learned for example about resistant starches, of which one is cooled potatoes: I ate the exact same dish but the first time, right after cooking, my levels shot up (not abnormally but you should ideally never have spikes, so your body doesn't have to keep pumping insulin), and then the second time, reheated, it was like I didn't eat anything. I was surprised so I researched and found https://www.webmd.com/diet/what-to-know-resistant-starches
Everyone is different so I definitely suggest to try them out for a month and see what gives you spikes in your diet. Then try to get rid of those spikes.