When you eat something there is post prandial spike in blood glucose which increases blood insulin levels .
Normally insulin is able to push these elevated glucose to inside of cell but in diabetes due to resistance they fail to do so . Therefore reason of postprandial hyperglycemia is decreased peripheral glucose uptake .
In fasting of more than 8 hours : you have not eaten anything still there’s hyperglycemia which can only be due to IMPAIRED liver function causing increased Gluconeogenesis .
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