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@Majid Naqvi
when you don't eat your liver will release some of its stored glucose, it's an automatic and natural response. It's not particularly a bad thing, and the reason many of us use intermittent fasting.
The sugar you are seeing in your blood has not just appeared out of thin air, It's just been stored away in your liver where you can't see it. Now because of your fast it's been moved into you blood where you can see it, and more importantly use it.
Think of your body as an overflowing sugar bowl, when you don't eat you can start to empty that bowl