They are frozen ones so very much the same size The potato is just an example of how the same food can test differently on different days. Others have said the same that their levels vary when testing the same foods. Our BG levels can react differently to the same foods tested at different times
I would never assume that you wouldn't get different readings for the same meal, different times, different days!
That's why it is essential to keep a food diary, as
@Bluetit1802 has mentioned, that it is trends over time that you really should monitor. Even different times of the year and what phase of the moon it is, can throw up unusual readings.
I don't think I've become obsessed with testing, (I think!) But if you have intolerance to a lot of foods as I have, I need to know by testing, experimenting, experience how to discover what different foods within those certain groups of foods I can eat.
As not being obsessed about testing, I once tested for about a week, baked beans.
I do love 'em but I did it and I set it out, so I could find out which brand, how many, sauce, no sauce, let cool, reheat in microwave, or in oven, or try them cold, with other foods, with different fatty foods including meat, veg and some salad stuff!
Well, I found out, that normal cooking, just beans was a definite no, none at all!
All brands! The only way I could eat beans, was to have about ten, warmed up in oven with meat that was fatty, with lots of salad veg!
Needless to say, I don't bother, as it is so much messing around!
It's not the only food that I've done this with! But you get the drift!
As I've said potatoes are my nemesis, just a little bit of a small roasties, even cooked in goose fat and roasted will give me a spike up to double figures from normal, every time, never mind what time, day or full moon!
So the great advice about having jacket potato with baked beans for a really good diabetic lunch would be so bad for me personally that I should put a claim in about medical negligence to the dietician, dsn and doctors that I had appointments with all them years, when I knew something was wrong, but they didn't have a clue!