Thanks to everyone's comments, I was able to make a few changes to my diet and cut down on those spikes over 9. I now eat like this:
- Very low-carb breakfast (typically a home-baked almond cake) with a little bit of fruit or cream, approx. 20g of carbs;
- Slow-carb lunch based on 150g of legumes (lentils, beans, etc.), meat or cheese, and vegetables, approx 40g of carbs;
- Fast-carb (the nasty ones that cause spikes) dinner consisting of e.g. baked potatoes or some grain, such as bulgur or bread along with veggies, fish/meat, etc.
What really helped was moving the nasty high GI carbs to dinner (thanks
@pinewood), cutting a bit on the volume, as well as injecting 30 mins ahead of the dinner meal. Depleting the body of carbs and/or stimulating the remaining insulin-producing function of pancreas by exercise before dinner certainly helped too.
Following this pattern has helped me keep my BS below 6.2 after breakfast, below 6.5 after lunch and below 7.2 after dinner in the past 2 days.