It could be anything. It could be your body's responses changing. It could be the weather. It could be what you ate. It could be anaemia. It could be sleeping too much. It could be not sleeping enough. It could be a mild infection. It could be lower next month. It could be a message to stop trying to do something impossible and to stop blaming yourself for something that is very good and not actually a problem.
This is why, as Maltida-Rose says, you should not be testing so close together. What matters is the general trend and working with that, not trying to micromanage it. You cannot keep going down forever, and you cannot stay static. There will always be variations from minute-to-minute, from day-to-day, from month-to-month.
Going from 38 to 40 is not a problem. 40 is not a problem.
Worrying about perfectly fine levels is a problem.
Do the best you can to manage your levels, and if they are within the normal range that is fine. Some months will be higher than others and that is fine. Keeping doing the best you can and see what they say next time. Trying to find exact causes of variations that are perfectly normal, that are at a perfectly good level will not help you. You cannot judge individual meals or days with an HbA1c, that is why you test before and after eating. You cannot do the impossible.
But if you are concerned about certain foods, cut them out for three months and see what it says then. It may be lower, and it may be a total coincidence, but it seems from this and other threads that is what is important to you. And as much as I do not think you have anything to worry about with your physical health unless things continue to head up and out of the normal HbA1c range, your mental health matters too.
You have asked about your no added sugar foods several times and it seems to me you have to options to choose between:
1/ stop eating those foods and try to get your levels as low as you can.
2/ accept that being in a healthy range is good and eat what you want within that.
You need to decide which matters more to you: the comfort of certain foods, or the comfort of you levels being as low as you can get them. Unfortunately you cannot have both, and this is clearly causing you worry and unhappiness. So it may not be easy, but sadly that is the choice you need to make.
Personally I would pick option 2, you are doing very well overall and if those foods make you happy and your levels are within healthy ranges I do not see a problem. If you go too low that can also be bad for you. And no matter how much you try, you are not going to get so healthy as to gain immortality. And why would you want to anyway if the effort to achieve it makes you unhappy?
Quality of life is as important as quantity of life. People climb mountains accepting the risks. You have to find the balance that works for you.
A level of 37 without the wafers you like.
A level of 40 with the wafers you like.
There is nothing wrong with a 40. Unless the 37 is more important to you than the wafers. Only you know that. Only you can decide that. Sorry, but you have to make that decision.
And stop over testing, it makes it meaningless and is bad for your mental health.
