Try testing whether it is food related, or not, by having a no carb brekkie (e.g. Bacon and eggs, no toast) and see if that stops the rise.
Likewise a lunch of meat and veg or salad. No rice, bread, potato...
You know where the carbs are. Just try doing without for a couple of meals.
If your BG stays stable, or drops, then you know that the food is the culprit.
Then it's just a matter of eliminating the items in question, or reducing portion sizes.
Sadly, our bodies change over time. I used to be able to eat potato. So I did. Perhaps too often. But I can't any more...
The alternative is medication, but I prefer to control by diet, since the body tends to get resistant to drugs, so it often turns into a drug escalation, and may lead to insulin, in time.